SYNTHESIS OF DEUTERATED ALDEHYDES

Abstract

Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.

Description

BACKGROUND

The recent surge in applications of deuterated pharmaceutical agents, including the FDA approval of the first deuterated drug, Austedo (deutetrabenazine) in 2017, has created an urgent demand for synthetic methods that efficiently generate deuterated building blocks. As one of the most widely utilized substances in synthesis, aldehydes serve as a synthetic linchpin enabling quick access to a wide array of fascinating and structurally diverse deuterated building blocks and to biologically important molecular architectures. Traditionally, deuterated aldehydes are produced from esters or amides by using reduction and/or oxidation sequences. Although these reagents can be employed to prepare both deuterated aromatic and aliphatic aldehydes, their high cost restricts their broad use. Other recent approaches to prepare deuterated aldehydes, such as functional group manipulation or hydrogen-deuterium exchange (HDE) catalysed by Ir or Ru, may involve intrinsic difficulties in controlling reactivity, non-selective deuteration, and/or high cost. Clearly, an urgent need exists for the development of a new processes that tolerate all types of aldehydes and is capable of achieving useful levels of deuterium incorporation (>95%).

SUMMARY OF THE INVENTION

In one aspect, the present disclosure relates to method for preparing a deuterated aldehyde of formula

R^Z—C(O)—D

wherein

R^Z is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^a, and R^Z is optionally deuterated; R^a at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted;

the method comprising:

contacting an aldehyde of formula

R^Z′—C(O)—H

with an N-heterocyclic carbene catalyst in a solvent comprising D₂O, thereby producing the deuterated aldehyde,

wherein R^Z′ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^b;

R^b at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted.

In some embodiments, the the N-heterocyclic carbene catalyst is a compound of formula (I)

wherein

W is S or NR^A

Q¹ is CR^C or N;

Q² is CR^D or N; or

Q¹-Q² is CR^x1R^y1—CR^x2R^y2;

R^A and R^B are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^C, and R^D are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^A and R^C, R^B and R^D, and/or R^C and R^D alternatively together with the N or C atoms they are attached to form a ring;

R^B alternatively is an alkylene forming a dimer;

R^x1, R^y1, R^x2, and R^y2 are each independently hydrogen or alkyl; and

X⁻ is counter ion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show different methods for the synthesis of deuterated aldehydes. FIG. 1A shows indirect approaches involving transformations of different functional groups to deuterated aldehydes. FIG. 1B shows direct approach employing transition metal catalyzed hydrogen-deuterium exchange of aromatic formyl groups. FIG. 1C shows a representative process of the present disclosure using organocatalytic direct hydrogen-deuterium exchange of the aromatic, aliphatic and α, β-unsaturated formyl group.

FIG. 2 shows the structures of various NHC catalysts.

FIGS. 3A and 3B show representative results of NHC catalysed HDE with aromatic aldehydes (61 examples). FIG. 3A shows representative results of NHC catalysed HDE with model aromatic aldehyde and representative catalysts. FIG. 3B shows representative results of NHC catalysed HDE with a variety of aromatic aldehydes. Unless specified, catalyst 5o is used. For products 7j, 7z, 7ad, 7ao, 7av-7ax, 7bd, and 7bf, 7bg, and 7i and 7bh-7bi, catalysts 5m, 5ag, and 5l, are used, respectively. Y refers to isolated yields of deuterated products. It is noted that protium aldehyde starting materials are completely converted in these reactions and the major side products arise from benzoin condensation, and D refers to D-incorporation percentages based on the calculation described herein.

FIG. 4A shows representative results of NHC catalysed HDE reactions of enals (20 examples) and representative catalysts. FIG. 4B shows representative results NHC catalysed HDE reactions of aliphatic aldehydes (23 examples) and representative catalysts. FIG. 4C shows representative results of amine catalysed selective α-dedeuteration of bis-deuterated aldehydes.

FIG. 5A representative results of gram scale synthesis carried out using the same conditions employed for small scale, similar yields and levels of deuteration incorporation level are obtained. Moreover, D₂O can be recycled and reused for subsequent HDE reactions without loss of the efficiency.

FIG. 5B shows representative results of Cannizzaro reaction for the synthesis of α, α-dideuterated benzylic alcohols.

FIG. 5C shows representative deuterated therapeutics prepared from the corresponding deuterated aromatic aldehydes. The benzylic positions in the therapeutics are easily metabolized sites.

DETAILED DESCRIPTION

The present relates to the use of N-heterocyclic carbenes (NHC) to promote a reversible hydrogen-deuterium exchange (HDE) reaction with aldehydes, which may lead to a practical approach to synthetically valued C-1 deuterated aldehydes. The process disclosed herein may be used to directly convert aldehydes to C-1 deuterated counterparts using cheap, safe and operationally convenient D₂O as the deuterium source under mild reaction conditions without requiring additional functionality manipulation and with minimal byproduct production. In particular embodiments, the reactivity of the well-established NHC catalysed formation of Breslow intermediates from aldehydes may be reengineered to overcome the overwhelmingly kinetically favorable, irreversible benzoin condensation reaction and achieve the critical reversibility to drive the formation of desired deuterated products when an excess of D₂O is employed. Remarkably, this operationally simple and cost-effective process disclosed herein may serve as a general and truly practical approach to a wide variety of 1-D-aldehydes including aryl, alkyl and alkenyl aldehydes, which are difficult to access by existing methods. Further, the process disclosed herein may remarkably enable chemoselective late-stage deuteration of complex, native therapeutic agents and natural products with uniformly high levels of deuterium incorporation (>95% for a total of 104 substrates probed).

1. DEFINITIONS

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present invention. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not.

The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). The modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The term “about” may refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean from 0.9-1.1. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4.

Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75^th Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito, 1999; Smith and March March's Advanced Organic Chemistry, 5^th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; Carruthers, Some Modern Methods of Organic Synthesis, 3^rd Edition, Cambridge University Press, Cambridge, 1987; the entire contents of each of which are incorporated herein by reference.

The term “alkoxy” as used herein, refers to an alkyl group, as defined herein, appended to the parent molecular moiety through an oxygen atom. Representative examples of alkoxy include, but are not limited to, methoxy, ethoxy, propoxy, 2-propoxy, butoxy and tert-butoxy.

The term “alkyl” as used herein, means a straight or branched, saturated hydrocarbon chain containing from 1 to 20 carbon atoms. The term “lower alkyl” or “C_1-6alkyl” means a straight or branched chain hydrocarbon containing from 1 to 6 carbon atoms. Representative examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

The term “alkenyl” as used herein, means an unsaturated hydrocarbon chain containing from 2 to 20 carbon atoms and at least one carbon-carbon double bond.

The term “alkynyl” as used herein, means an unsaturated hydrocarbon chain containing from 2 to 20 carbon atoms and at least one carbon-carbon triple bond.

The term “alkylene”, as used herein, refers to a divalent group derived from a straight or branched chain hydrocarbon of 1 to 10 carbon atoms, for example, of 2 to 5 carbon atoms. Representative examples of alkylene include, but are not limited to, —CH₂CH₂—, —CH₂CH₂CH₂—, —CH₂CH₂CH₂CH₂—, and —CH₂CH₂CH₂CH₂CH₂—.

The term “aryl” as used herein, refers to a phenyl group, or a bicyclic fused ring system. Bicyclic fused ring systems are exemplified by a phenyl group appended to the parent molecular moiety and fused to a cycloalkyl group, as defined herein, a phenyl group, a heteroaryl group, as defined herein, or a heterocycle, as defined herein. Representative examples of aryl include, but are not limited to, indolyl, naphthyl, phenyl, quinolinyl and tetrahydroquinolinyl.

The term “haloalkyl” as used herein, means an alkyl group, as defined herein, in which one, two, three, four, five, six, seven or eight hydrogen atoms are replaced by a halogen. Representative examples of haloalkyl include, but are not limited to, 2-fluoroethyl, 2,2,2-trifluoroethyl, trifluoromethyl, difluoromethyl, pentafluoroethyl, and trifluoropropyl such as 3,3,3-trifluoropropyl.

The term “cycloalkyl” as used herein, means a monovalent group derived from an all-carbon ring system containing zero heteroatoms as ring atoms, and zero double bonds. The all-carbon ring system can be a monocyclic, bicylic, or tricyclic ring system, and can be a fused ring system, a bridged ring system, or a spiro ring system, or combinations thereof. Examples of cycloalkyls include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and

The cycloalkyl groups described herein can be appended to the parent molecular moiety through any substitutable carbon atom.

The term “cycloalkenyl” as used herein, means a non-aromatic monocyclic or multicyclic ring system containing at least one carbon-carbon double bond and preferably having from 5-10 carbon atoms per ring. Exemplary monocyclic cycloalkenyl rings include cyclopentenyl, cyclohexenyl or cycloheptenyl.

The term “halogen” as used herein, means Cl, Br, I, or F.

The term “heteroaryl” as used herein, refers to an aromatic monocyclic ring or an aromatic bicyclic ring system or an aromatic tricyclic ring system. The aromatic monocyclic rings are five or six membered rings containing at least one heteroatom independently selected from the group consisting of N, O, and S (e.g. 1, 2, 3, or 4 heteroatoms independently selected from O, S, and N). The five membered aromatic monocyclic rings have two double bonds and the six membered six membered aromatic monocyclic rings have three double bonds. The bicyclic heteroaryl groups are exemplified by a monocyclic heteroaryl ring appended to the parent molecular moiety and fused to a monocyclic cycloalkyl group, as defined herein, a monocyclic aryl group, as defined herein, a monocyclic heteroaryl group, as defined herein, or a monocyclic heterocycle, as defined herein. The tricyclic heteroaryl groups are exemplified by a monocyclic heteroaryl ring appended to the parent molecular moiety and fused to two of a monocyclic cycloalkyl group, as defined herein, a monocyclic aryl group, as defined herein, a monocyclic heteroaryl group, as defined herein, or a monocyclic heterocycle, as defined herein. Representative examples of monocyclic heteroaryl include, but are not limited to, pyridinyl (including pyridin-2-yl, pyridin-3-yl, pyridin-4-yl), pyrimidinyl, pyrazinyl, thienyl, furyl, thiazolyl, thiadiazolyl, isoxazolyl, pyrazolyl, and 2-oxo-1,2-dihydropyridinyl. Representative examples of bicyclic heteroaryl include, but are not limited to, chromenyl, benzothienyl, benzodioxolyl, benzotriazolyl, quinolinyl, thienopyrrolyl, thienothienyl, imidazothiazolyl, benzothiazolyl, benzofuranyl, indolyl, quinolinyl, imidazopyridine, benzooxadiazolyl, and benzopyrazolyl. Representative examples of tricyclic heteroaryl include, but are not limited to, dibenzofuranyl and dibenzothienyl. The monocyclic, bicyclic, and tricyclic heteroaryls are connected to the parent molecular moiety through any carbon atom or any nitrogen atom contained within the rings.

The term “heterocycle” or “heterocyclic” as used herein, means a monocyclic heterocycle, a bicyclic heterocycle, or a tricyclic heterocycle. The monocyclic heterocycle is a three-, four-, five-, six-, seven-, or eight-membered ring containing at least one heteroatom independently selected from the group consisting of O, N, and S. The three- or four-membered ring contains zero or one double bond, and one heteroatom selected from the group consisting of O, N, and S. The five-membered ring contains zero or one double bond and one, two or three heteroatoms selected from the group consisting of O, N and S. The six-membered ring contains zero, one or two double bonds and one, two, or three heteroatoms selected from the group consisting of O, N, and S. The seven- and eight-membered rings contains zero, one, two, or three double bonds and one, two, or three heteroatoms selected from the group consisting of O, N, and S. Representative examples of monocyclic heterocycles include, but are not limited to, azetidinyl, azepanyl, aziridinyl, diazepanyl, 1,3-dioxanyl, 1,3-dioxolanyl, 1,3-dithiolanyl, 1,3-dithianyl, 1,3-dimethylpyrimidine-2,4(1H,3H)-dione, imidazolinyl, imidazolidinyl, isothiazolinyl, isothiazolidinyl, isoxazolinyl, isoxazolidinyl, morpholinyl, oxadiazolinyl, oxadiazolidinyl, oxazolinyl, oxazolidinyl, oxetanyl, piperazinyl, piperidinyl, pyranyl, pyrazolinyl, pyrazolidinyl, pyrrolinyl, pyrrolidinyl, tetrahydrofuranyl, tetrahydropyranyl, tetrahydropyridinyl, tetrahydrothienyl, thiadiazolinyl, thiadiazolidinyl, 1,2-thiazinanyl, 1,3-thiazinanyl, thiazolinyl, thiazolidinyl, thiomorpholinyl, 1,1-dioxidothiomorpholinyl (thiomorpholine sulfone), thiopyranyl, and trithianyl. The bicyclic heterocycle is a monocyclic heterocycle fused to a phenyl group, or a monocyclic heterocycle fused to a monocyclic cycloalkyl, or a monocyclic heterocycle fused to a monocyclic cycloalkenyl, or a monocyclic heterocycle fused to a monocyclic heterocycle, or a spiro heterocycle group, or a bridged monocyclic heterocycle ring system in which two non-adjacent atoms of the ring are linked by an alkylene bridge of 1, 2, 3, or 4 carbon atoms, or an alkenylene bridge of two, three, or four carbon atoms. Representative examples of bicyclic heterocycles include, but are not limited to, benzopyranyl, benzothiopyranyl, chromanyl, 2,3-dihydrobenzofuranyl, 2,3-dihydrobenzothienyl, 2,3-dihydroisoquinoline, 2-azaspiro[3.3]heptan-2-yl, azabicyclo[2.2.1]heptyl (including 2-azabicyclo[2.2.1]hept-2-yl), 2,3-dihydro-1H-indolyl, isoindolinyl, octahydrocyclopenta[c]pyrrolyl, octahydropyrrolopyridinyl, and tetrahydroisoquinolinyl. Tricyclic heterocycles are exemplified by a bicyclic heterocycle fused to a phenyl group, or a bicyclic heterocycle fused to a monocyclic cycloalkyl, or a bicyclic heterocycle fused to a monocyclic cycloalkenyl, or a bicyclic heterocycle fused to a monocyclic heterocycle, or a bicyclic heterocycle in which two non-adjacent atoms of the bicyclic ring are linked by an alkylene bridge of 1, 2, 3, or 4 carbon atoms, or an alkenylene bridge of two, three, or four carbon atoms. Examples of tricyclic heterocycles include, but are not limited to, octahydro-2,5-epoxypentalene, hexahydro-2H-2,5-methanocyclopenta[b]furan, hexahydro-1H-1,4-methanocyclopenta[c]furan, aza-adamantane (1-azatricyclo[3.3.1.1^3,7]decane), and oxa-adamantane (2-oxatricyclo[3.3.1.1^3,7]decane). The monocyclic, bicyclic, and tricyclic heterocycles are connected to the parent molecular moiety through any carbon atom or any nitrogen atom contained within the rings.

In some instances, the number of carbon atoms in a hydrocarbyl substituent (e.g., alkyl or cycloalkyl) is indicated by the prefix “C_x-y” or “C_x-C_y—”, wherein x is the minimum and y is the maximum number of carbon atoms in the substituent. Thus, for example, “C_1-4alkyl” or “C₁-C₄-alkyl” refers to an alkyl substituent containing from 1 to 4 carbon atoms.

The molecules and substituent groups as described herein are not deuterated, unless explicitly indicated otherwise. The term “deuterated” as used herein refers to a molecule or substituent group in which 1, 2, 3, 4, 5, 6, 7, or 8 hydrogen atoms are replaced by deuterium.

The term “N-heterocyclic carbene catalyst” refers to a heterocyclic compound, or a salt thereof, that has at least one nitrogen and a carbene carbon (C:) as members of the heterocyclic ring.

The term “level of deuterium incorporation” as used herein refers to the extent of deuterium labeling as determined by ¹H NMR spectroscopy, and is measured by percentage deuteration as shown in Equation 1.

$\begin{array}{cc}\%\mathrm{Deuteration}=100-\left[\left(\frac{\mathrm{residual}\mathrm{integral}}{\mathrm{number}\mathrm{of}\mathrm{labelling}\mathrm{sites}}\right)\times 100\right]& \mathrm{Equation}1\end{array}$

For compounds described herein, groups and substituents thereof may be selected in accordance with permitted valence of the atoms and the substituents, such that the selections and substitutions result in a stable compound, e.g., which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc.

For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are explicitly contemplated

2. METHOD

Traditionally, deuterated aldehydes are produced from esters (FIG. 1A, reaction A) or amides (reaction B) by using reduction and/or oxidation sequences. Although these reagents can be employed to prepare both deuterated aromatic and aliphatic aldehydes, their high cost restricts their broad use. Recently, several approaches were reported for the synthesis of aromatic deuterated aldehydes from the corresponding aryl iodides (reaction C), carboxylic acids (reaction D), or benzyl halides (reaction E). High yielding hydrogen-deuterium exchange (HDE) processes catalysed by Ir (FIG. 1B, reaction F, D₂ as deuterium source) or Ru (reaction G, D₂O as deuterium source) were developed to produce deuterated aromatic aldehydes directly without the need for functional group manipulation. However, it is recognized that an intrinsic difficulty exists in controlling reactivity (reactions C and F), which often cause accompanying non-selective deuteration of aromatic rings. Furthermore, these protocols only resulted in moderate degrees of D-incorporation (14-84%) and their use is restricted to aromatic aldehydes.

Kinetically controlled, irreversible reactions have dominated in organic synthesis. In contrast, reversible reactions have been much less studied, probably because the surmountable energy barriers for the forward and reverse reaction present the daunting challenge in controlling the selectivity. This is particularly problematic for isodesmic reactions, in which all bonds broken in the reactants are reformed in the products. However, this strategy may provide opportunities for developing unique transformations that are difficult to be achieved by traditional, irreversible approaches. The present disclosure demonstrates that organocatalytic N-heterocyclic carbenes (NHC) may promote isodesmic hydrogen-deuterium exchange (HDE) reactions with a wide variety of aldehydes, including aryl, alkyl and alkenyl aldehydes (FIG. 1C). This process may directly convert aldehydes to C-1 deuterated counterparts using cheap, safe and operationally convenient D₂O as the deuterium source under mild reaction conditions without requiring additional functionality manipulation and with minimal byproduct production.

Without being limited by any theory, it is hypothesized that Breslow intermediates may be redirected to create a novel isodesmic HDE process for transforming readily accessible aldehydes into their 1-D-analogs. Specifically, a reaction of an aldehyde with an NHC carried out in D₂O may reversibly produce the deuterated Breslow intermediate 3 (Process I) and that 3 may react with D₂O to produce the desired deuterated aldehyde 2D with concurrent regeneration of the catalyst. Driving the reversible reaction towards the desired product 2D may be achieved by the formation of more stable C—D bond (bond energy of C—D as 341.4 kJ/mol and C—H as 338 kJ/mol) and by employing a large access amount of D₂O. Under specific circumstances, the thermodynamic process may be complicated by the existence of competitive, kinetically favored benzoin condensation reaction that is known to occur under the reaction conditions (Process II). In particular, the HDE reactions of electron-withdrawing group (EWG) substituted aromatic aldehydes may be more prone to undergo condensation reactions with Breslow intermediates (e.g., 4).

In one aspect, the present disclosure relates to a a deuterated aldehyde of formula,

R^Z—C(O)—D

wherein

R^Z is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^a, and R^Z is optionally deuterated;

R^a at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted;

the method comprising:

contacting an aldehyde of formula

R^Z′—C(O)—H

with an N-heterocyclic carbene catalyst in a solvent comprising D₂O, thereby producing the deuterated aldehyde,

wherein R^Z′ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^b;

R^b at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted.

In some embodiments, R^Z is an optionally substituted aryl or an optionally substituted heteroaryl. For example, R^Z may be

each of which is optionally substituted.

In some embodiments, R^Z is an optionally substituted alkenyl or an optionally substituted cycloalkenyl. For example, R^Z may be

wherein

R¹ and R² are independently hydrogen, alkyl, aryl, or heteroaryl, wherein the alkyl, aryl, and heteroaryl are optionally substituted; and

R³ is hydrogen, alkyl, or aryl, wherein the alkyl and aryl are optionally substituted, or

R¹ and R³ together with the carbon atoms to which they are attached form a 6- to 8-membered ring, which is optionally substituted.

In some embodiments, R^Z is an optionally substituted alkyl or an optionally substituted cycloalkyl. In some embodiments, R^Z is R^W—(CR^aaR^bb)_p—, wherein

R^W is hydrogen, deuterium, —NH(benzyloxycarbonyl), alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, and heterocyclyl are optionally substituted;

R^aa and R^bb at each occurrence are independently hydrogen, deuterium, alkyl, —NH(t-butoxycarbonyl), or —O-benzyl; and

p is 1, 2, 3, 4, 5, 6, 7, or 8.

In some embodiments, R^Z′ has a structure that is the same as the structure of R^Z. In some embodiments, R^Z is a deuterated group, and R^Z′ has a structure that is different from the structure of R^Z only in that the positions corresponding to the deuterium atoms in R^Z are occupied by hydrogen in R^Z′. In other words, R^Z′ may be a non-deuterated equivalent of a deuterated R^Z group. In some embodiments, the method as disclosed herein may produce R^Z—C(O)—D, in which R^Z is deuterated, from a starting material R^Z′—C(O)—H, in which R^Z′ is not deuterated.

In some embodiments, the solvent further comprises an organic solvent. The organic solvent may include, for example, tetrahydrofuran (THF), dichloromethane (CH₂Cl₂ or DCM), toluene, or a combination thereof.

In some embodiments, the reaction disclosed herein may be carried out in the presence of a base, such as K₂CO₃, KOAc, N, N-Diisopropylethylamine (DIPEA), NaHCO₃, or a combination thereof.

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I)

wherein

W is S or NR^A

Q¹ is CR^C or N;

Q² is CR^D or N; or

Q¹-Q² is CR^x1R^y1—CR^x2R^y2;

R^A and R^B are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^C, and R^D are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^A and R^C, R^B and R^D, and/or R^C and R^D alternatively together with the N or C atoms they are attached to form a ring;

R^B alternatively is an alkylene forming a dimer;

R^x1, R^y1, R^x2, and R^y2 are each independently hydrogen or alkyl; and

X⁻ is counter ion.

In some embodiments, W is NR^A.

In some embodiments, Q¹ is CR^C and Q² is CR^D. In some embodiments, Q¹ is CR^C and Q² is N. In some embodiments, Q¹-Q² is CR^x1R^y1—CR^x2R^y2.

In some embodiments, W is NR^A, R^A and R^B are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl, and R^C and R^D are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl.

In some embodiments, W is NR^A, and R^A and R^C, R^B and R^D, or R^C and R^D together with the N or C atoms they are attached to form a ring.

In some embodiments, Q¹-Q² is CR^x1R^y1—CR^x2R^y2, and R^A and R^B are as defined above. In some some embodiments, Q¹-Q² is CR^x1R^yl—CR^x2R^y2, and R^A and R^B are each independently an optionally substituted aryl, such as an optionally substituted phenyl.

In some embodiments, the N-heterocyclic carbene catalyst of formula (I) is a compound of formula (I-a), (I-b), (I-c), or (I-d)

wherein

G¹ is an optionally substituted heterocycle; and

G² is an optionally substituted aryl;

R^A, R^B, R^x1, R^y1, and X⁻ are as defined in formula (I).

In some embodiments, X⁻ is Cl⁻, Br⁻, I⁻, or BF₄⁻. Other suitable counter ion may be used for the present method.

Suitable N-heterocyclic carbene catalysts of formula (I) include a compound selected from the group consisting of

in which Mes is

and Dipp is

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and R^Z is an optionally substituted aryl or an optionally substituted heteroaryl. For example, in these embodiments, the N-heterocyclic carbene catalyst is

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), such as 5m, 5o, 5l, or 5ag, and R^Z is

each of which is optionally substituted.

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-c), and R^Z is an optionally substituted alkenyl or an optionally substituted cycloalkenyl. For example, in these embodiments, the N-heterocyclic carbene catalyst is

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-c), such as 5p or 5l, and R^Z is

wherein

R¹ and R² are independently hydrogen, alkyl, aryl, or heteroaryl, wherein the alkyl, aryl, and heteroaryl are optionally substituted; and

R³ is hydrogen, alkyl, or aryl, wherein the alkyl and aryl are optionally substituted, or

R¹ and R³ together with the carbon atoms to which they are attached form a 6- to 8-membered ring, which is optionally substituted.

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and R^Z is an optionally substituted alkyl or an optionally substituted cycloalkyl. For example, in these embodiments, the N-heterocyclic carbene catalyst is

In some embodiments, the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), such as 5q or 5af, and R^Z is R^W—(CR^aaR^bb)—, wherein

R^W is hydrogen, deuterium, —NH(benzyloxycarbonyl), alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, and heterocyclyl are optionally substituted;

R^aa and R^bb at each occurrence are independently hydrogen, deuterium, alkyl, —NH(t-butoxycarbonyl), or —O-benzyl; and

p is 1, 2, 3, 4, 5, 6, 7, or 8.

In some embodiments, the method disclosed herein further includes isolating the produced deuterated aldehyde. Suitable method for isolating the deuterated aldehyde product may include those known in the art, such as chromatographic procedures.

In some embodiments, the method disclosed herein produces a level of deuterium incorporation of the —C(O)—D moiety of at least 90%. The level of deuterium incorporation of the —C(O)—D moiety may be at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or even at least 99.5%. The level of deuterium incorporation of the —C(O)—D moiety may be about 90% to 99.9%, about 92% to 99.9%, about 95% to 99.9%, about 97% to 99.9%, or even about 99% to 99.9%. In particular embodiments, the level of deuterium incorporation of the —C(O)—D moiety is at least 95%.

In another aspect, the present disclosure provides a deuterated aldehyde produced by the method disclosed herein.

In another aspect, the present disclosure provides an isolated deuterated aldehyde produced by the method disclosed herein.

The deuterated aldehyde or isolated deuterated aldehyde products as disclosed herein may be used as starting materials for the preparation of other compounds, including, for example, deuterated alcohols and deuterated pharmaceutical compounds.

Compound names are assigned by using Struct=Name naming algorithm as part of CHEMDRAW® ULTRA v. 12.0.

The compound may exist as a stereoisomer wherein asymmetric or chiral centers are present. The stereoisomer is “R” or “S” depending on the configuration of substituents around the chiral carbon atom. The terms “R” and “S” used herein are configurations as defined in IUPAC 1974 Recommendations for Section E, Fundamental Stereochemistry, in Pure Appl. Chem., 1976, 45: 13-30. The disclosure contemplates various stereoisomers and mixtures thereof and these are specifically included within the scope of this invention. Stereoisomers include enantiomers and diastereomers, and mixtures of enantiomers or diastereomers. Individual stereoisomers of the compounds may be prepared synthetically from commercially available starting materials, which contain asymmetric or chiral centers or by preparation of racemic mixtures followed by methods of resolution well-known to those of ordinary skill in the art. These methods of resolution are exemplified by (1) attachment of a mixture of enantiomers to a chiral auxiliary, separation of the resulting mixture of diastereomers by recrystallization or chromatography and optional liberation of the optically pure product from the auxiliary as described in Furniss, Hannaford, Smith, and Tatchell, “Vogel's Textbook of Practical Organic Chemistry”, 5th edition (1989), Longman Scientific & Technical, Essex CM20 2JE, England, or (2) direct separation of the mixture of optical enantiomers on chiral chromatographic columns or (3) fractional recrystallization methods.

It should be understood that the compound may possess tautomeric forms, as well as geometric isomers, and that these also constitute an aspect of the invention.

3. EXAMPLES

General Information. Commercial reagents and solvents were used as received, unless otherwise stated. Organic solution was concentrated under reduced pressure on a Büchi rotary evaporator. Analytical thin layer chromatography (TLC) was performed on 0.25 mm silica gel plates (Qingdao Haiyang Chemical China), and the compounds were visualized with a UV light at 254 nm. Further visualization was achieved by staining with iodine. Flash chromatography was performed on silica gel 200-300 mesh (purchased from Qingdao Haiyang Chemical China) with commercial solvents (purchased from Adamas-beta®). The ¹H NMR and ¹³C NMR spectra were recorded on a Bruker AM 400 Spectrometer (400 and 100 MHz for ¹H NMR and ¹³C NMR, respectively) and are internally referenced to residual solvent signals (note: CDCl₃ referenced at 7.26 ppm in ¹H NMR; DMSO-d⁶ referenced at 2.50 ppm in ¹H NMR, respectively). Multiplicities were given as s (singlet), d (doublet), t (triplet), dd (double of doublet), and m (multiplets). Coupling constants were reported in Hertz (Hz). Data for ¹³C NMR are reported in terms of chemical shift. High-resolution mass spectrometry (HRMS) was recorded on Waters LCT Premier XE spectrometer. The NHC catalysts 5d, 5e and 5s were purchased from Adamas-beta, and 5a, 5b, 5c, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 5o, 5q, 5r, 5t, 5u, 5v, 5w, 5x, 5y, 5z, 5aa, 5ab, 5ac, 5ad, 5ae, 5af, 5ag, 5ai, 5aj, 5ak, 5al were prepared according to literature procedures.

The level of deuterium incorporation in the substrate was determined by ¹H NMR spectroscopy. The integrals were calibrated against a peak corresponding to a position not expected to be labelled. The extent of labeling (percentage of deuteration) at any specific position was calculated using Equation 1.

$\begin{array}{cc}\%\mathrm{Deuteration}=100-\left[\left(\frac{\mathrm{residual}\mathrm{integral}}{\mathrm{number}\mathrm{of}\mathrm{labelling}\mathrm{sites}}\right)\times 100\right]& \mathrm{Equation}1\end{array}$

Example 1. NHC Promoted HDE Process for Aromatic Aldehydes

The HDE process of the electron-neutral 2-naphthaldehyde (6a) was studied using various NHC catalysts (FIG. 2), catalyst loading, base, solvent, time and temperature, and amount of D₂O (Table 1). These experiments led to establishment of the reagents, time and temperatures that promote most efficient HED reactions. Specifically, for effective reactions, it may be advantageous to utilize bulky NHC catalysts such as the N,N-dimesityl- or 2,6-diisopropy-imidazolium bromides 5m or 5o, 5-10 mol % K₂CO₃, NaHCO₃ or KOAc as base (1.0 equiv), toluene or CH₂Cl₂ containing 1/4 v/v D₂O as solvent, temperatures in the 40-60° C. range and a 12 h reaction time (FIG. 3A).

TABLE 1
Reaction Conditions for Aromatic Aldehydea
Entry	Catalyst	Solvent	T (° C.)	Yield (%)b	D (%)c
1	—	THF	60	98	0
2	5a	THF	60	40	99
3	5b-i	THF	60	0-99	5-80
4	5j	THF	60	40	11
5	5k	THF	60	26	98
6	5l	THF	60	15	90
7	5m	THF	60	50	94
8	5n	THF	60	26	99
9	5o	THF	60	48	98
10	5o	THF	40	58	97
11	5o	THF	25	96	8
12	5o	CH2Cl2	40	80	98
13	5o	toluene	40	81	98
14d	5o	toluene	40	73	98
15e	5o	toluene	40	40	98
16f	5o	toluene	40	82	97
17g	5o	toluene	40	81	91
aReaction conditions unless otherwise stated: 6a (0.5 mmol), catalysts 5 (10 mol %) and K2CO3 (1.0 equiv) in D2O (1 mL) and solvent (0.25 mL) was vigorously stirred for 12 hours.
bIsolated yield.
cDetermined by 1H NMR.
d5% catalyst was used.
e20% catalyst was used.
f0.5 mL D2O was used.
g10 eq D2O was used.

A study using various aromatic aldehydes (FIG. 3B) showed that the conditions needed to bring about maximum yields and high levels of D-incorporation may be substrate dependent (61 examples). Under appropriate conditions, HDE reactions of structurally diverse benzaldehydes and heteroaromatic aldehydes take place with uniformly high to excellent levels of D-incorporation (95-99%). Electron-poor aromatic aldehydes are competent substrates to deliver corresponding deuterated aldehydes in moderate to good yields (44-86%) (7c, 7k-7p, 7s-7w, 7aa-ab, and 7ae). Of particular note is the observation that the strong electron-withdrawing 3-nitro group substituted benzaldehyde 7w undergoes smooth HDE when 5o (5 mol %) is utilized as the catalyst, KOAc is employed as the base and 80° C. is the temperature. In contrast, reactions of electron-rich aryl aldehydes (7b, 7e, 7f, 7q, 7r, 7x-7z, 7ac, 7ad, 7ah-al) take place in higher yields as a consequence of the attenuation of undesired benzoin condensations. Notably, free phenolic hydroxyl groups have limited effects on the exchange reactions, as is demonstrated by the observations that 7y and 7an produce the deuterio-analogs with 98% D-incorporation. Moreover, the methodology may be employed to introduce deuterium into a substrate (6ag) containing two aldehyde groups. In this case, efficient double HDE occurs to produce the bis-deuterated counterpart 7ag in high yield and with an excellent level of D-incorporation. In addition to benzaldehyde derivatives, various electron-rich (7ap-7ar, 7au-7ax, 7bc-7bd, 7bc, 7bd) and poor (7as, 7at, 7ay-7bb) heteroaromatics, and polycyclic aromatics (7am-7ao) are viable substrates for the new HDE reaction. Finally, advantages associated with the mild nature and selectivity of the new metal free methodology are illustrated by the tolerance of transition metal sensitive halogen substituted substrates (7c, 7l, 7s, 7t, 7aa, 7ab, 7at, 7az and 7ba). Of further significance is the observation that the protocol enables late-stage HDE exchange reactions of structurally complex aldehydes (7be-7bi) in impressive yields (52-73%) and levels of D-incorporation (96-98%). Remarkably, the level of D-incorporation can be improved by simply carrying out a second HDE reaction with the product of an initial HDE reaction (eg. 7v from 95% to 99%).

Example 2. NHC Catalysed HDE for Enals and Aliphatic Aldehydes

Formation of 1-D-substituted enals using the NHC catalysed HDE process was also studied (FIG. 4A). These reactions may involve potentially more problematic substrates owing to their higher tendency to form γ-butyrolactones 11 under NHC catalysis conditions. Furthermore, unexpectedly the conditions and NHC catalysts used to promote HDE reactions of aromatic aldehydes do not lead to deuteration of enals like cinnamaldehyde (Table 2).

TABLE 2
Reaction Conditions for Cinnamaldehydea
Entry	Catalyst	Base	T (° C.)	Yield (%)b	% Dd	Yield (%)c
1	5a	K2CO3	40	—	—	50
2	5b	K2CO3	40	—	—	50
3	5m	K2CO3	40	60	0	10
4	5o	K2CO3	40	80	0	0
5	5r	K2CO3	40	—	—	—
6	5l	KOAc	40	—	—	—
7	5l	DIPEA	40	20	20	—
8	5s	KOAc	40	92	0	—
9	5t	KOAc	40	80	0	—
10	5u	KOAc	40	87	7	—
11	5v	KOAc	40	60	15	—
12	5w	KOAc	40	87	4	—
13	5x	KOAc	40	65	0	—
14	5y	KOAc	40	55	4	—
15	5z	KOAc	40	33	12	—
16	5aa	KOAc	40	80	0	—
17	5ab	KOAc	40	20	18	—
18	5ac	KOAc	40	40	40	—
19	5ad	KOAc	40	43	22	—
20	5ae	KOAc	40	72	0	—
21	5af	KOAc	40	50	32	—
22	5ag	KOAc	40	86	58	—
23	5ag	KOAc	60	95	45	—
24	5ah	KOAc	60	67	95	—
25	5p	KOAc	60	63	97	—
aReaction conditions unless otherwise stated: 9a (0.25 mmol), catalyst 5 (10 mol %) and KOAc (1.0 equiv) in D2O (1 mL) and DCM (0.25 mL) was vigorously stirred at 40° C. for 12 hours.
bYield of isolated product of 10a.
cYield of isolated product of 11.
dDeuterium incorporations (%) were determined by 1H NMR spectroscopy.

As shown in FIG. 4A, HDE reaction of cinnamaldehyde promoted by the triazolium salt 5p generates the corresponding 1-D-analog 10a in 63% yield with 97% D-incorporation. The process using 5p represents a general approach to the preparation of deuterated cinnamaldehyde derivatives 10b-f (95-99% D-incorporation in albeit moderate yields). In HDE reactions of 2,3-disubstituted enals 9g-q, use of triazolium salt 5l rather than 5p enables formation of the corresponding 1-D-aldehydes with uniformly high levels of D-incorporation (97-99%) (Table 3). Further, under the mild reaction conditions, HDE reactions of sensitive β-nonsubstituted enals 9r-t take place smoothly to produce the corresponding deuterated aldehydes 10r-t.

TABLE 3
Reaction Conditions for Other Enalsa
Entry	Catalyst	T (° C.)	Yield (%)b	% Dc
1	5a	25	98	0
2	5b	25	96	0
3	5m	25	92	0
4	5o	25	95	0
5	5r	25	94	15
6	5ag	25	89	67
7	5l	25	96	94
8	5l	40	95	98
aReaction conditions unless otherwise stated: 9g (0.25 mmol), catalyst 5 (10 mol %) and KOAc (1.0 equiv) in D2O (1 mL) and DCM (0.25 m) was vigorously stirred at 25° C. for 12 hours.
bYield of isolated product.
cDeuterium incorporations (%) were determined by 1H NMR spectroscopy.

The roles played by aliphatic aldehydes (alkanals) in organic synthesis are equal to those of aromatic aldehydes and enals. However, the preparation of 1-D analogs of alkanals remains an unsolved problem. Furthermore, as compared with aromatic and α,β-unsaturated counterparts, alkanals have been used less often in NHC catalysed processes. These issues are associated with the presence in alkanals of multiple reactive sites, particularly enolizable α-positions, at which side reactions can occur.

Further studies were conducted to assess the applicability of the new NHC promoted HDE reactions to alkanals, and there results demonstrated that optimal conditions are substrate dependent (Table 4). An extensive evaluation of catalysts revealed the nitro-group containing imidazolinium salt 5q may be an ideal choice. In reactions using 5q as catalyst, NaHCO₃ as base and CH₂Cl₂ as solvent, a large number of structurally diverse alkanals, such as linear 11a-k (R²=H), α-branched 11l-q, amine α-functionalized 11r and complex 11s-w derivatives are efficiently transformed to their respective 1-D-analogs (FIG. 4B). Notably, benzyl protected D-ribofuranose and D-glucose bearing hemiacetal can effectively participate in the process with 5af as promoter to give only α-deuterated products 12u-v. This protocol is complementary to a Ru-catalysed HDE process, in which deuterium substitutes hydrogen occurring at the hydroxyl tethered carbon. Furthermore, the new protocol enables highly chemoselective deuteration of the aldehyde moiety in the densely functionalized macrolide antibiotic midecamycin (11w). In some experiments, deuteration also takes place at α- and/or β-positions of alkanals. However, a C1-deuterated aldehyde may be produced by subjecting the bis-deuterio product to a base promoted exchange reaction in H₂O. For example, treatment of 12l with pyrrolidine derivative 13 in H₂O/CH₂Cl₂ forms the 1-D-aldehyde 14 in 81% yield (FIG. 4C).

TABLE 4
Reaction Conditions for Aliphatic Aldehydes a
Entry	Catalyst	T (° C.)	Yield (%)b	% D1c	% D2c
1	5a	40	35	12	37
2	5b	40	55	35	41
3	5c	40	71	30	84
4	5g	40	—	—	—
5	5h	40	65	0	76
6	5i	40	44	11	48
7	5j	40	52	40	97
8	5k	40	64	73	95
9	5l	40	39	60	97
10	5m	40	32	98	98
11	5n	40	33	95	98
12	5o	40	35	95	81
13	5ai	40	70	10	95
14	5aj	40	85	7	15
15	5ak	40	40	83	82
16	5al	40	65	18	45
17	5q	40	64	98	92
18	5q	30	73	99	97
a Reaction conditions unless otherwise stated 11l (0.5 mmol), catalysts 5 (10 mol %) and NaHCO3 (1.0 equiv) in D2O (1 mL) and DCM (0.25 mL) was vigorously stirred at 40° C. for 12 hours.
bYield of isolated product.
cDeuterium incorporations (%) were determined by 1H NMR spectroscopy.

Example 3 Experiment Procedures and Product Characterization

General Procedure for Deuteration of Aldehydes Catalysed by NHC

Aldehyde (1 equiv), NHC catalyst (x mol %) and base (1 equiv) were dissolved in a mixture of D₂O (1 mL) and organic solvent (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at specified temperature for 12 hours. After cooling to room temperature, the reaction was extracted with DCM, dried over anhydrous sodium sulfate, concentrated in vacuo, and purified by column chromatography to afford the deuterated product. The level of deuterium incorporation of the product was determined by ¹H NMR spectroscopy. The integrals were calibrated against Equation 1.

2-Naphthaldehyde-α-d₁ (7a)

2-Naphthaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7c was obtained as a white solid in 81% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.14 (s, 0.02H), 8.31 (s, 1H), 8.00-7.88 (m, 4H), 7.66-7.56 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 192.0 (t, J=26.6 Hz), 136.4 (s), 134.6 (s), 134.0 (t, J=3.5 Hz), 132.6 (s), 129.5 (s), 129.1 (s), 129.1 (s), 128.1 (s), 127.1 (s), 122.7 (s); HRMS (EI): m/z caled for C₁₁H₇DO [(M)⁺]: 157.0638, found: 157.0639.

4-Methoxybenzaldehyde-α-d₁ (7b)

4-Methoxybenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7a was obtained as a colorless oil in 93% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.86 (s, 0.02H), 7.82 (dt, J=8.8, 2.4 Hz, 2H), 6.98 (dt, J=8.8, 2.4 Hz, 2H), 3.87 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=26.3 Hz), 164.6 (s), 132.0 (s), 129.9 (t, J=3.5 Hz), 114.3 (s), 55.6 (s); HRMS (EI): m/z caled for C₈H₇DO₂ [(M)⁺]: 137.0587, found: 137.0588.

4-Bromobenzaldehyde-α-d₁ (7c)

4-Bromobenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7b was obtained as a yellow solid in 86% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.96 (s, 0.02H), 7.73 (dt, J=8.4, 2.0 Hz, 2H), 7.66 (dt, J=8.4, 2.0 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.8 (t, J=26.8 Hz), 135.0 (t, J=3.7 Hz), 132.4 (s), 131.0 (s), 129.8 (s); HRMS (EI): m/z caled for C₇H₄DBrO [(M)⁺]: 184.9587, found: 184.9589.

Benzaldehyde-α-d₁ (7d)

Benzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7d was obtained as a colorless oil in 70% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.02 (s, 0.03H), 7.90-7.87 (m, 2H), 7.64 (t, J=7.4 Hz, 1H), 7.54 (t, J=7.5 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 192.1 (t, J=26.5 Hz), 136.3 (t, J=3.6 Hz), 134.5 (s), 129.8 (s), 129.0 (s); HRMS (EI): m/z caled for C₇H₅DO [(M)⁺]: 107.0481, found: 107.0482.

4-Methylbenzaldehyde-α-d₁ (7e)

4-Methylbenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7e was obtained as a colorless oil in 74% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.95 (s, 0.02H), 7.77 (dd, J=8.4, 1.6 Hz, 2H), 7.32 (dd, J=8.3, 0.5 Hz, 2H), 2.43 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.7 (t, J=26.3 Hz), 145.6 (s), 134.1 (t, J=3.6 Hz), 129.9 (s), 129.7 (s), 21.9 (s); HRMS (EI): m/z caled for C₈H₇DO [(M)⁺]: 121.0638, found: 121.0639.

4-Benzyloxybenzaldehyde-α-d₁ (7f)

4-Benzyloxybenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7f was obtained as a yellow solid in 98% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.89 (s, 0.02H), 7.84 (d, J=8.8 Hz, 2H), 7.46-7.35 (m, 5H), 7.08 (d, J=8.8 Hz, 2H), 5.15 (s, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=26.2 Hz), 163.8 (s), 136.0 (s), 132.0 (s), 130.1 (t, J=3.5 Hz), 128.8 (s), 128.4 (s), 127.5 (s), 115.2 (s), 70.3 (s); HRMS (EI): m/z caled for C₁₄H₁₁DO₂ [(M)⁺]: 213.0900, found: 213.0904.

[1,1′-Biphenyl]-4-carbaldehyde-α-d₁ (7g)

[1,1′-biphenyl]-4-carbaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7g was obtained as a white solid in 95% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.06 (s, 0.02H), 7.96 (d, J=8.4 Hz, 2H), 7.75 (d, J=8.4 Hz, 2H), 7.66-7.62 (m, 2H), 7.51-7.46 (m, 2H), 7.45-7.39 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 191.7 (t, J=26.5 Hz), 147.2 (s), 139.7 (s), 135.1 (t, J=3.5 Hz), 130.3 (s), 129.1 (s), 128.5 (s), 127.7 (s), 127.4 (s); HRMS (EI): m/z caled for C₁₃H₉DO [(M)⁺]: 183.0794, found: 183.0796.

4-Acetoxybenzaldehyde-α-d₁ (7h)

4-Acetoxybenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7h was obtained colorless as a oil in 47% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.99 (s, 0.03H), 7.92 (d, J=8.6 Hz, 2H), 7.28 (d, J=8.6 Hz, 2H), 2.34 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 190.6 (t, J=26.6 Hz), 168.7 (s), 155.4 (s), 133.9 (t, J=3.6 Hz), 131.2 (s), 122.4 (s), 21.2 (s); HRMS (EI): m/z caled for C₉H₇DO₃ [(M)⁺]: 165.0536, found: 165.0537.

4-Dimethylaminobenzaldehyde-α-d₁ (7i)

4-Dimethylaminobenzaldehyde (0.5 mmol), 5ag (30 mol %) and AcOK (1 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7i was obtained as a white solid in 83% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.73 (s, 0.02H), 7.73 (d, J=9.0 Hz, 2H), 6.69 (d, J=9.0 Hz, 2H), 3.07 (s, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 190.1 (t, J=25.8 Hz), 154.4 (s), 132.0 (s), 125.0 (t, J=3.4 Hz), 111.0 (s), 40.1 (s); HRMS (EI): m/z caled for C₉H₁₀DNO [(M)⁺]: 150.0903, found: 150.0903.

4-Acetamidobenzaldehyde-1,2-d₁,d₃ (7j)

4-Acetamidobenzaldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7j was obtained as a white solid in 64% yield with 99% D-incorporation at position 1 and 8% D-incorporation at position 2. ¹H NMR (400 MHz, DMSO-d₆) δ 10.38 (s, 1H), 9.86 (s, 0.01H), 7.85 (d, J=8.8 Hz, 2H), 7.78 (d, J=8.8 Hz, 2H), 2.13-2.05 (m, 2.77H); ¹³C NMR (100 MHz, DMSO-d₆) δ 191.2 (t, J=26.7 Hz), 169.1 (s), 144.8 (s), 131.0 (s), 130.8 (s), 118.5 (s), 24.2-23.7 (m); HRMS (EI): m/z caled for C₉H₈DNO₂ [(M)⁺]: 164.0696 Found: 164.0696; C₉H₇D₂NO₂ [(M)⁺]: 165.0759, found: 165.0758.

4-Fluorobenzaldehyde-α-d₁ (7k)

4-Fluorobenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7k was obtained as a colorless oil in 50% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.97 (s, 0.02H), 7.93-7.89 (m, 2H), 7.25-7.18 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.2 (t, J=26.6 Hz), 166.6 (d, J=256.7 Hz), 132.9 (t, J=3.3 Hz), 132.3 (d, J=9.7 Hz), 116.4 (d, J=22.3 Hz); HRMS (EI): m/z caled for C₇H₄DFO [(M)⁺]: 125.0387, found: 125.0386.

4-Chlorobenzaldehyde-α-d₁ (7l)

4-Chlorobenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7l was obtained as a shite solid in 79% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃): δ 9.96 (s, 0.02H), 7.81 (d, J=8.6 Hz, 2H), 7.49 (d, J=8.6 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃): δ 190.6 (t, J=26.7 Hz), 141.0 (s), 134.6 (t, J=3.7 Hz), 130.9 (s), 129.5 (s); HRMS (EI): m/z caled for C₇H₄DClO [(M)⁺]: 141.0092, found: 141.0091.

4-Formylbenzonitrile-α-d₁ (7m)

4-formylbenzonitrile (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7m was obtained as a yellow solid in 75% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.08 (s, 0.02H), 7.99 (d, J=8.4 Hz, 2H), 7.84 (d, J=8.4 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.4 (t, J=27.2 Hz), 138.7 (t, J=3.7 Hz), 132.9 (s), 129.9 (s), 117.76 (s), 117.6 (s); HRMS (EI): m/z caled for C₈H₄DNO [(M)⁺]: 132.0434, found: 132.0436.

4-(Trifluoromethyl)benzaldehyde-α-d₁ (7n)

4-(Trifluoromethyl)benzaldehyde (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7n was obtained as a yellow oil in 44% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.10 (s, 0.02H), 8.01 (d, J=8.2 Hz, 2H), 7.81 (d, J=8.2 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.8 (t, J=27.0 Hz), 138.6 (s), 135.6 (q, J=32.6 Hz), 129.9 (s), 126.1 (q, J=3.8 Hz), 123.4 (d, J=272.9 Hz); HRMS (EI): m/z caled for C₈H₄DF₃O [(M)⁺]: 175.0355, found: 175.0356.

Methyl 4-formylbenzoate-α-d₁ (7o)

Methyl 4-formylbenzoate (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7o was obtained as a white solid in 68% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.08 (s, 0.01H), 8.18 (dt, J=8.4, 1.6 Hz, 2H), 7.94 (dt, J=8.5, 2.0 Hz, 2H), 3.94 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.4 (t, J=26.9 Hz), 166.1 (s), 139.1 (t, J=3.6 Hz), 135.1 (s), 130.2 (s), 129.5 (s), 52.6 (s); HRMS (EI): m/z caled for C₇H₉DO₃: 165.0536, found: 165.0538.

4-Formyl-N-isopropylbenzamide-α-d₁ (7p)

4-Formyl-N-isopropylbenzamide (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7p was obtained as a white solid in 75% yield with 99% D-incorporation. ¹H NMR (400 MHz, DMSO-d₆) δ 10.07 (s, 0.01H), 8.45 (d, J=7.6 Hz, 1H), 8.02 (d, J=8.5 Hz, 2H), 7.98 (d, J=8.4 Hz, 2H), 4.15-4.07 (m, 1H), 1.17 (d, J=6.6 Hz, 6H); ¹³C NMR (100 MHz, DMSO-d₆) δ 192.6 (t, J=26.9 Hz), 164.5 (s), 139.8 (s), 137.5 (s), 129.3 (s), 127.9 (s), 41.2 (s), 22.2 (s); HRMS (EI): m/z caled for C₁₁H₁₂DNO₂ [(M)⁺]: 192.1009, found: 192.1011.

3-Methoxybenzaldehyde-α-d₁ (7q)

3-methoxybenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7q was obtained as a yellow oil in 92% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.95 (s, 0.03H), 7.46-7.40 (m, 2H), 7.37 (d, J=2.0 Hz, 1H), 7.18-7.14 (m, 1H), 3.84 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.8 (t, J=26.6 Hz), 160.2 (s), 137.7 (t, J=3.6 Hz), 130.0 (s), 123.5 (s), 121.5 (s), 112.0 (s), 55.5 (d, J=1.1 Hz); HRMS (EI): m/z caled for C₈H₇DO₂ [(M)⁺]: 137.0587, found: 137.0588.

m-Tolualdehyde-α-d₁ (7r)

M-Tolualdehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7r was obtained as a colorless oil in 91% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.98 (s, 0.02H), 7.70-7.67 (m, 2H), 7.46-7.39 (m, 2H), 2.43 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 192.3 (t, J=26.5 Hz), 138.9 (s), 136.4 (t, J=3.5 Hz), 135.3 (s), 130.0 (s), 128.9 (s), 127.2 (s), 21.2 (s); HRMS (EI): m/z caled for C₈H₇DO [(M)⁺]: 121.0638, found: 121.0639.

3-Chlorobenzaldehyde-α-d₁ (7s)

3-Chlorobenzaldehyde (0.5 mmol), 5o (5 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7s was obtained as a colorless oil in 71% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.97 (s, 0.02H), 7.85 (t, J=1.8 Hz, 1H), 7.76 (dt, J=7.6, 1.2 Hz, 1H), 7.62-7.58 (m, 1H), 7.48 (t, J=7.8 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=27 Hz), 137.8 (t, J=3.7 Hz), 135.5 (s), 134.4 (s), 130.4 (s), 129.3 (s), 128.0 (s); HRMS (EI): m/z caled for C₇H₄DClO [(M)⁺]: 141.0092, found: 141.0091.

3-Bromobenzaldehyde-α-d₁ (7t)

3-Bromobenzaldehyde (0.5 mmol), 5o (5 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7t was obtained as a colorless oil in 86% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.95 (s, 0.01H), 8.00 (t, J=1.7 Hz, 1H), 7.80 (dt, J=7.6, 1.2 Hz, 1H), 7.76-7.72 (m, 1H), 7.42 (t, J=7.8 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 190.4 (t, J=26.9 Hz), 137.9 (t, J=3.7 Hz), 137.3 (s), 132.4 (s), 130.6 (s), 128.4 (s), 123.4 (s); HRMS (EI): m/z caled for C₇H₄DBrO [(M)⁺]: 184.9587, found: 184.9588.

3-Formylbenzonitrile-α-d₁ (7u)

3-Formylbenzonitrile (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 3-formylbenzonitrile-α-d₁ was obtained as a yellow solid in 81% yield with 95% D-incorporation.

3-Formylbenzonitrile-α-d₁ (95% D, 0.40 mmol), 5o (10 mol %) and KOAc (0.40 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours again. 7u was obtained as a colorless solid in 59% yield (for two steps) with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.04 (s, 0.01H), 8.16 (s, 1H), 8.12 (d, J=7.8 Hz, 1H), 7.91 (d, J=7.7 Hz, 1H), 7.69 (t, J=7.7 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 188.7 (t, J=27.2 Hz), 136.2 (s), 135.8 (t, J=3.8 Hz), 132.3 (s), 132.1 (s), 129.1 (s), 116.6 (s), 112.7 (s); HRMS (EI): m/z caled for C₈H₄DNO [(M)⁺]: 132.0434, found: 132.0435.

Methyl 3-formylbenzoate-α-d₁ (7v)

Methyl 3-formylbenzoate (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7v was obtained as a yellow oil in 59% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.07 (s, 0.01H), 8.54-8.52 (m, 1H), 8.29 (dt, J=7.6, 1.6 Hz, 1H), 8.08 (dt, J=7.7, 1.4 Hz, 1H), 7.63 (t, J=11.4, 1H), 3.96 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.1 (t, J=26.8 Hz), 166.0 (s), 136.5 (d, J=3.5 Hz), 135.2 (s), 133.1 (s), 131.3 (d, J=7.1 Hz), 129.3 (s), 52.5 (s); HRMS (EI): m/z caled for C₇H₉DO₃[(M)⁺]: 165.0536, found: 165.0538.

3-Nitrobenzaldehyde-α-d₁ (7w)

3-Nitrobenzaldehyde (0.5 mmol), 5o (5 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7w was obtained as a yellow solid in 55% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.12 (s, 0.01H), 8.72 (s, 1H), 8.51-8.48 (m, 1H), 8.24 (d, J=7.6, 1H), 7.77 (t, J=7.9 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 189.5 (t, J=27.3 Hz), 148.8 (s), 137.3 (t, J=3.8 Hz), 134.7 (s), 130.4 (s), 128.6 (s), 124.5 (s); HRMS (EI): m/z caled for C₇H₄NDO₃ [(M)⁺]: 152.0332, found: 152.0333.

2-Methoxybenzaldehyde-α-d₁ (7x)

2-Methoxybenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7x was obtained as a yellow oil in 95% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.43 (s, 0.02H), 7.79 (dd, J=7.7, 1.8 Hz, 1H), 7.54-7.49 (m, 1H), 7.00-6.93 (m, 2H), 3.88 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 189.5 (t, J=27.5 Hz), 161.9 (s), 136.0 (s), 128.4 (s), 124.7 (t, J=3.3 Hz), 120.6 (s), 111.6 (s), 55.6 (s); HRMS (EI): m/z caled for C₈H₇DO₂ [(M)⁺]: 137.0587, found: 137.0588.

Salicylaldehyde-α-d₁ (7y)

Salicylaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7y was obtained as a colorless oil in 47% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 11.04 (s, 1H), 9.89 (s, 0.01H), 7.57-7.50 (m, 2H), 7.04-6.97 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 196.3 (t, J=26.9 Hz), 161.7 (s), 137.0 (s), 133.7 (s), 120.6 (t. J=3.0 Hz), 119.9 (s), 117.6 (s); HRMS (EI): m/z caled for C₇H₅DO₂ [(M)⁺]: 123.0431, found: 123.0432.

N-(2-Formylphenyl)acetamide-α-d₁ (7z)

N-(2-Formylphenyl)acetamide (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7z was obtained as a yellow solid in 90% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 11.15 (s, 1H), 9.92 (s, 0.01H), 8.74 (d, J=8.5 Hz, 1H), 7.68 (dd, J=7.6, 1.5 Hz, 1H), 7.61 (dt, J=8.5, 1.5 Hz, 1H), 7.23 (t, J=7.5 Hz, 1H), 2.26 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.2 (t, J=27.0), 169.6 (s), 140.9 (s), 136.2 (s), 136.0 (s), 122.8 (s), 121.3 (t, J=3.0 Hz), 119.7 (s), 25.4 (s); HRMS (EI): m/z caled for C₉H₈DNO₂ [(M)⁺]: 164.0696, found: 164.0697.

2-Chloorbenzaldehyde-α-d₁ (7aa)

2-chloorbenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7aa was obtained as a yellow oil in 79% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.47 (s, 0.03H), 7.91 (dd, J=7.7, 1.6 Hz, 1H), 7.52 (dt, J=8.1, 1.7 Hz, 1H), 7.44 (d, J=7.3 Hz, 1H), 7.40-7.35 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 189.5 (t, J=27.8 Hz), 138.0 (s), 135.1 (s), 132.4 (t, J=3.5 Hz), 130.6 (s), 129.4 (s), 127.3 (s); HRMS (EI): m/z caled for C₇H₄DClO [(M)⁺]: 141.0092, found: 141.0090.

2-Bromobenzaldehyde-α-d₁ (7ab)

2-Bromobenzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ab was obtained as a yellow oil in 93% yield with 99% D-incorporation. ¹H NMR (400 MHz, DMSO) δ 10.33 (s, 0.01H), 7.90-7.87 (m, 1H), 7.63-7.60 (m, 1H), 7.45-7.37 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.4 (t, J=27.9 Hz), 134.3 (s), 132.8 (s), 132.4 (t, J=3.5 Hz), 128.8 (s), 126.9 (s), 126.1 (s); HRMS (EI): m/z caled for C₇H₄DBrO [(M)⁺]: 184.9587, found: 184.9586.

2,3-Dimethylbenzalde-α-d₁ (7ac)

2,3-Dimethylbenzalde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ac was obtained as a colorless oil in 83% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.22 (s, 0.02H), 7.56 (d, J=7.7 Hz, 1H), 7.29 (d, J=7.4 Hz, 1H), 7.16 (t, J=7.6 Hz, 1H), 2.49 (s, 3H), 2.25 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 192.9 (t, J=26.4 Hz), 139.2 (s), 138.3 (s), 135.3 (s), 134.3 (t, J=3.4 Hz), 129.8 (s), 125.8 (s), 20.0 (s), 14.4 (s); HRMS (EI): m/z caled for C₉H₉DO [(M)⁺]: 135.0794, found: 135.0795.

2,4-DiMethylbenzaldehyde-α-d₁ (7ad)

2,4-DiMethylbenzaldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ad was obtained as a colorless oil in 88% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.18 (s, 0.02H), 7.68 (d, J=7.8 Hz, 1H), 7.14 (d, J=7.8 Hz, 1H), 7.05 (s, 1H), 2.62 (s, 3H), 2.37 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 192.1 (t, J=26.3 Hz), 144.6 (s), 140.6 (s), 132.6 (s), 132.4 (s), 132.06-131.9 (t, J=3.4 Hz), 127.1 (s), 21.7 (s), 19.6 (s); HRMS (EI): m/z caled for C₉H₉DO [(M)⁺]: 135.0794, found: 135.0795.

2-Chloro-3-fluorobenzaldehyde-α-d₁ (7ae)

2-Chloro-3-fluorobenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ae was obtained as a white solid in 86% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.44 (s, 0.02H), 7.74-7.71 (m, 1H), 7.42-7.33 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 188.2 (td, J=28.1, 3.8 Hz), 158.4 (d, J=250.8 Hz), 133.9 (t, J=3.5), 128.0 (d, J=7.4 Hz), 124.9 (d, J=18.5 Hz), 124.7 (d, J=3.5 Hz), 121.8 (d, J=21.4 Hz); HRMS (EI): m/z caled for C₇H₃DClFO [(M)⁺]: 158.9997, found: 158.9998.

4-Formyl-3-methoxybenzonitrile-α-d₁ (7af)

4-Formyl-3-methoxybenzonitrile (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7af was obtained as a yellow solid in 81% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.49 (s, 0.01H), 7.91 (d, J=7.9 Hz, 1H), 7.34 (d, J=7.9 Hz, 1H), 7.29 (s, 1H), 4.00 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 188.0 (t, J=28.2 Hz), 161.3 (s), 129.2 (s), 127.5 (t, J=3.4 Hz), 124.4 (s), 118.5 (s), 117.8 (s), 115.4 (s), 56.2 (s); HRMS (EI): m/z caled for C₉H₆DNO₂ [(M)⁺]: 162.0540, found: 162.0541.

Isophthalaldehyde-1,3-d₁,d₁ (7ag)

Isophthalaldehyde (0.5 mmol), 5o (20 mol %) and KOAc (1 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ag was obtained as a white solid in 68% yield with 97.5% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.10 (s, 0.05H), 8.37 (t, J=1.4 Hz, 1H), 8.15 (dd, J=7.6, 1.6 Hz, 2H), 7.72 (t, J=7.6 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 190.8 (t, J=27 Hz), 136.9 (t, J=3.7 Hz), 134.7 (s), 131.0 (s), 129.9 (s); HRMS (EI): m/z caled for C₈H₄D₂O₂ [(M)⁺]: 136.0493, found: 136.0494.

Piperonal-α-d₁ (7ah)

Piperonal (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ah was obtained as a colorless solid in 98% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.79 (s, 0.01H), 7.39 (dd, J=7.9, 1.5 Hz, 1H), 7.31 (d, J=1.5 Hz, 1H), 6.91 (d, J=7.9 Hz, 1H), 6.06 (s, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.0 (t, J=26.5 Hz), 153.1 (s), 148.7 (s), 131.8 (t, J=3.6 Hz), 128.7 (s), 108.4 (s), 106.9 (s), 102.1 (s); HRMS (EI): m/z caled for C₈H₅DO₃ [(M)⁺]: 151.0380, found: 151.0381.

1,4-Benzodioxin-6-carboxaldehyde-α-d₁ (7ai)

1,4-Benzodioxin-6-carboxaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ai was obtained as a yellow solid in 99% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.80 (s, 0.02H), 7.40-7.37 (m, 2H), 6.98-6.94 (m, 1H), 4.34-4.26 (m, 4H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=26.4 Hz), 149.3 (s), 143.9 (s), 130.6 (t, J=3.6 Hz), 124.2 (s), 118.4 (s), 117.8 (s), 64.7 (s), 64.1 (s); HRMS (EI): m/z caled for C₉H₇DO₃ [(M)⁺]: 165.0536, found: 165.0537.

2,3-(Methylenedioxy)benzaldehyde-α-d₁ (7aj)

2,3-(Methylenedioxy)benzaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7aj was obtained as a colorless solid in 81% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.09 (s, 0.03H), 7.25 (dd, J=7.7, 1.2 Hz, 1H), 6.99 (dd, J=7.7, 1.2 Hz, 1H), 6.90 (t, J=7.9 Hz, 1H), 6.10 (s, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 186.7 (t, J=27.1 Hz), 148.2 (s), 147.9 (s), 120.7 (s), 120.1 (s), 118.3 (t, J=3.6 Hz), 112.4 (s), 101.5 (s); HRMS (EI): m/z caled for C₈H₅DO₃ [(M)⁺]: 151.0380, found: 151.0381.

3,4,5-Trimethoxybenzaldehyde-α-d₁ (7ak)

3,4,5-Trimethoxybenzaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ak was obtained as a white solid in 88% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.79 (s, 0.01H), 7.06 (s, 2H), 3.87 (s, 3H), 3.86 (s, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 190.7 (t, J=26.6 Hz), 153.6 (s), 143.5 (s), 131.6 (t, J=3.2 Hz), 106.6 (s), 60.9 (d, J=2.6 Hz), 56.2 (d, J=2.5 Hz); HRMS (EI): m/z caled for C₁₁H₁₁DO₄ [(M)⁺]: 197.0798, found: 197.0796.

2,2-Dimethyl-4H-benzo[d][1,3]dioxine-6-carbaldehyde-α-d₁ (7al)

2,2-Dimethyl-4H-benzo[d][1,3]dioxine-6-carbaldehyde (0.5 mmol), 5o (10 mol %), K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7al was obtained as a in 88% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.81 (s, 0.02H), 7.66 (dd, J=8.5, 2.0 Hz, 1H), 7.51 (t, J=0.8 Hz, 1H), 6.89 (d, J=8.5 Hz, 1H), 4.86 (s, 2H), 1.53 (s, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=26.3 Hz), 156.8 (s), 130.4 (s), 129.3 (t, J=3.4 Hz), 126.9 (s), 119.7 (s), 117.7 (s), 100.76 (s), 60.6 (s), 24.8 (s); HRMS (EI): m/z caled for C₁₁H₁₁DO₃ [(M)⁺]: 193.0849, found: 193.0850.

1-Naphthaldehyde-α-d₁ (7am)

1-Naphthaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7am was obtained as a colorless oil in 88% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.27 (s, 0.02H), 9.23 (d, J=8.7 Hz, 1H), 7.92 (d, J=8.2 Hz, 1H), 7.82-7.75 (m, 2H), 7.62-7.57 (m, 1H), 7.51-7.42 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 193.2 (t, J=26.5 Hz), 136.7 (s), 135.2 (s), 133.7 (s), 131.4-131.1 (m), 130.4 (s), 129.0 (s), 128.5 (s), 126.9 (s), 124.9 (s); HRMS (EI): m/z caled for C₁₁H₇DO [(M)⁺]: 157.0638, found: 157.0638.

2-Hydroxy-1-naphthaldehyde-α-d₁ (7an)

2-Hydroxy-1-naphthaldehyde (0.5 mmol), 5o (20 mol %) and NaHCO₃ (1 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7an was obtained as a white solid in 65% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 13.18 (s, 1H), 10.73 (s, 0.02H), 8.26 (d, J=8.5 Hz, 1H), 7.92 (d, J=9.1 Hz, 1H), 7.76 (d, J=8.0 Hz, 1H), 7.62-7.55 (m, 1H), 7.44-7.38 (m, 1H), 7.10 (d, J=9.1 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 182.9 (t, J=26.8 Hz), 165.0 (s), 139.1 (s), 132.9 (s), 129.5 (s), 129.1 (s), 127.8 (s), 124.5 (s), 119.2 (s), 118.6 (s), 111.2 (t, J=2.5 Hz); HRMS (EI): m/z caled for C₁₁H₇DO₂ [(M)⁺]: 173.0587, found: 173.0588.

9-Anthraldehyde-α-d₁ (7ao)

9-Anthraldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ao was obtained as a yellow solid in 88% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 11.37 (s, 0.01H), 8.87 (d, J=9.0 Hz, 2H), 8.48 (s, 1H), 7.91 (d, J=8.4 Hz, 2H), 7.63-7.57 (m, 2H), 7.50-7.43 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 191.4 (t, J=26.5 Hz), 134.0 (s), 130.9 (s), 129.8 (s), 128.1 (s), 127.9 (s), 124.5 (s), 123.2 (t, J=3.2 Hz), 122.3 (s); HRMS (EI): m/z caled for C₁₅H₉DO [(M)⁺]: 207.0794, found: 207.0796.

Thiophene-3-carboxaldehyde-α-d₁ (7ap)

Thiophene-3-carboxaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ap was obtained as a yellow oil in 67% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.94 (s, 0.02H), 8.13 (dd, J=2.8, 1.1 Hz, 1H), 7.56 (dd, J=5.1, 1.0 Hz, 1H), 7.39 (dd, J=5.1, 2.9 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 184.7 (t, J=26.8 Hz), 143.0 (t, J=3.8 Hz), 136.8 (s), 127.4 (s), 125.4 (s); HRMS (EI): m/z caled for C₅H₃DOS [(M)⁺]: 113.0046, found: 113.0047.

5-Methylthiophene-2-carboxaldehyde-α-d₁ (7aq)

5-Methylthiophene-2-carboxaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7aq was obtained as a yellow oil in 84% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.77 (s, 0.03H), 7.57 (d, J=3.6 Hz, 1H), 6.86 (d, J=3.6 Hz, 1H), 2.54 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 182.4 (t, J=26.9 Hz), 151.7 (s), 141.9 (t, J=4.9 Hz), 137.4 (s), 127.1 (s), 16.3 (s); HRMS (EI): m/z caled for C₆H₅DOS [(M)⁺]: 127.0202, found: 127.0203.

5-Methyl furfural-α-d₁ (7ar)

5-Methyl furfural (0.5 mmol), 5o (20 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ar was obtained as a yellow oil in 50% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.49 (s, 0.01H), 7.15 (d, J=3.5 Hz, 1H), 6.22 (dd, J=3.5, 0.8 Hz, 1H), 2.40 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 176.6 (t, J=27.9 Hz), 159.8 (s), 151.8 (t, J=4.7 Hz), 124.0 (s), 109.5 (s), 14.1 (s); HRMS (EI): m/z caled for C₆H₅DO₂: 111.0431, found: 111.0432.

4-Methoxy-3-pyridinecarboxaldehyde-α-d₁ (7as)

4-Methoxy-3-pyridinecarboxaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7as was obtained as a yellow solid in 98% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.39 (s, 0.02H), 8.82 (s, 1H), 8.58 (d, J=5.9 Hz, 1H), 6.90 (d, J=5.9 Hz, 1H), 3.95 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 187.4 (t, J=27.8 Hz), 165.7 (s), 155.1 (s), 149.9 (s), 119.5 (t, J=3.4 Hz), 106.3 (s), 54.9 (d, J=1.3 Hz); HRMS (EI): m/z caled for C₇H₆DNO₂ [(M)⁺]: 138.0540, found: 138.0541.

2,6-Dichloro-3-pyridinecarbaldehyde-α-d₁ (7at)

2,6-Dichloro-3-pyridinecarbaldehyde (0.5 mmol), 5o (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7at was obtained as a white solid in 93% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.38 (d, J=0.7 Hz, 0.02H), 8.18 (d, J=8.1 Hz, 1H), 7.43 (d, J=8.1 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 187.7 (t, J=28.6 Hz), 155.4 (s), 152.9 (s), 140.0 (s), 127.6 (t, J=3.7 Hz), 124.2 (s); HRMS (EI): m/z caled for C₆H₂DCl₂NO [(M)⁺]: 175.9654, found: 175.9656.

Benzothiophene-2-carboxaldehyde-α-d₁ (7au)

Benzothiophene-2-carboxaldehyde (0.5 mmol), 5o (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7au was obtained as a yellow solid in 58% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.08 (s, 0.02H), 8.0 (s, 1H), 7.92 (d, J=8.0 Hz, 1H), 7.87 (d, J=8.0 Hz, 1H), 7.51-7.45 (m, 1H), 7.44-7.38 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 184.5 (t, J=27.4 Hz), 143.3 (t, J=5.0 Hz), 142.7 (s), 138.6 (s), 134.6 (s), 128.2 (s), 126.3 (s), 125.3 (s), 123.3 (s); HRMS (EI): m/z caled for C₉H₅DOS [(M)⁺]: 163.0202, found: 163.0203.

Tosyl-1H-indole-5-carboxaldehyde-α-d₁ (7av)

Tosyl-1H-indole-5-carboxaldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7av was obtained as a yellow solid in 85% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.01 (s, 0.01H), 8.10 (d, J=8.6 Hz, 1H), 8.05 (d, J=1.0 Hz, 1H), 7.85 (dd, J=8.6, 1.5 Hz, 1H), 7.78 (d, J=8.4 Hz, 2H), 7.67 (d, J=3.7 Hz, 1H), 7.24 (d, J=8.1 Hz, 2H), 6.77 (dd, J=3.7, 0.5 Hz, 1H), 2.33 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.5 (t, J=26.4 Hz), 145.6 (s), 138.1 (s), 134.9 (s), 132.1 (t, J=2.9 Hz), 130.9 (s), 130.1 (s), 128.0 (s), 126.9 (s), 125.2 (s), 124.8 (s), 113.9 (s), 109.4 (s), 21.6 (s); HRMS (EI): m/z caled for C₁₆H₁₂DNO₃S [(M)⁺]: 300.0679, found: 300.0681.

Tosyl-1H-indole-3-carboxaldehyde-α-d₁ (7aw)

Tosyl-1H-indole-3-carboxaldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7aw was obtained yellow solid in 62% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.09 (s, 0.01H), 8.25 (d, J=9.1 Hz, 1H), 8.24 (s, 1H), 7.95 (d, J=8.1 Hz, 1H), 7.85 (d, J=8.4 Hz, 2H), 7.44-7.33 (m, 2H), 7.28 (d, J=8.1 Hz, 2H), 2.36 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 185.2 (t, J=26.6), 146.2 (s), 136.3 (s), 135.2 (s), 134.3 (s), 130.4 (s), 127.3 (s), 126.3 (s), 125.1 (s), 122.6 (s), 122.2 (t, J=3.4), 113.3 (s), 21.7 (s); HRMS (EI): m/z caled for C₁₆H₁₂DNO₃S [(M)⁺]: 300.0679, found: 300.0681.

3-Benzofurancarboxaldehyde-α-d₁ (7ax)

3-Benzofurancarboxaldehyde (0.5 mmol), 5m (10 mol %) and K₂CO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7ax was obtained as a white solid in 56% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.18 (s, 0.01H), 8.28 (s, 1H), 8.22-8.18 (m, 1H), 7.58-7.54 (m, 1H), 7.45-7.37 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 184.5 (t, J=26.7 Hz), 156.0 (s), 155.4 (s), 126.3 (s), 124.9 (s), 123.6 (t, J=3.9 Hz), 122.9 (s), 122.6 (s), 111.7 (s); HRMS (EI): m/z caled for C₉H₅DO₂ [(M)⁺]: 147.0431, found: 147.0432.

4-Quinoline carboxaldehyde-α-d₁ (7ay)

4-Quinoline carboxaldehyde (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ay was obtained as a white solid in 69% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.49 (s, 0.02H), 9.18 (d, J=4.2 Hz, 1H), 9.00 (dd, J=8.8, 0.9 Hz, 1H), 8.20 (dd, J=8.6, 0.5 Hz, 1H), 7.83-7.78 (m, 1H), 7.77 (d, J=4.2 Hz, 1H), 7.75-7.69 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 191.5 (t, J=27.2 Hz), 149.4 (s), 148.2 (s), 135.6 (t, J=3.7 Hz), 129.2 (s), 129.0 (s), 128.4 (s), 124.7 (s), 123.4 (s), 122.9 (s); HRMS (EI): m/z caled for C₁₀H₆DNO [(M)⁺]: 158.0590, found: 158.0591.

2-Chloroqinoline-3-carboxaldehyde-α-d₁ (7az)

2-Chloroqinoline-3-carboxaldehyde (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (2 mL) and toluene (0.5 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7az was obtained as a yellow solid in 73% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.54 (s, 0.01H), 8.74 (s, 1H), 8.05 (d, J=8.5 Hz, 1H), 7.97 (d, J=8.2 Hz, 1H), 7.91-7.83 (m, 1H), 7.64 (t, J=7.6 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 188.8 (t, J=28.3 Hz), 150.1 (s), 149.6 (s), 140.3 (s), 133.6 (s), 129.7 (s), 128.6 (s), 128.2 (s), 126.5 (s), 126.3 (t, J=3.4 Hz); HRMS (EI): m/z caled for C₁₀H₅DClNO [(M)⁺]: 192.0201, found: 192.0202.

6-Methoxy2-Chloroqinoline-3-carboxaldehyde-α-d₁ (7ba)

6-Methoxy2-Chloroqinoline-3-carboxaldehyde (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (2 mL) and toluene (0.5 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 6-Methoxy-2-chloroqinoline-3-carboxaldehyde-α-d₁ was obtained as a white solid in 93% yield with 94% D-incorporation.

6-Methoxy2-Chloroqinoline-3-carboxaldehyde-α-d₁ (deuteration 94%, 0.46 mmol), 5o (10 mol %) and KOAc (0.46 mmol, 1 equiv) was dissolved in a mixture of D₂O (2 mL) and toluene (0.5 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7ba was obtained as a yellow solid in 69% yield (for two steps) with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.53 (s, 0.01H), 8.62 (s, 1H), 7.94 (d, J=9.2 Hz, 1H), 7.50 (dd, J=9.2, 2.7 Hz, 1H), 7.17 (d, J=2.7 Hz, 1H), 3.94 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 189.1 (t, J=27.8 Hz), 158.8 (s), 147.7 (s), 145.8 (s), 138.7 (s), 129.9 (s), 127.8 (s), 126.6 (s), 126.3 (t, J=3.3 Hz), 106.4 (s), 55.8 (s); HRMS (EI): m/z caled for C₁₁H₇DClNO₂ [(M)⁺]: 222.0306, found: 222.0308.

Isoquinoline-4-carbaldehyde-α-d₁ (7bb)

Isoquinoline-4-carbaldehyde (0.5 mmol), 5o (10 mol %) and KOAc (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7bb was obtained as a yellow solid in 84% yield with 96% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.29 (s, 0.04H), 9.32 (s, 1H), 9.08 (d, J=8.4 Hz, 1H), 8.84 (s, 1H), 7.97 (d, J=8.4 Hz, 1H), 7.83-7.77 (m, 1H), 7.67-7.61 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 192.5 (t, J=26.8 Hz), 158.3 (s), 152.8 (s), 133.5 (s), 132.2 (s), 128.4 (s), 128.3 (s), 128.3 (s), 124.7 (t, J=3.5 Hz), 124.3 (s); HRMS (EI): m/z caled for C₁₀H₆DNO [(M)⁺]: 158.0590, found: 158.0591.

N-Ethyl-3-carbazolecarboxaldehyde-α-d₁ (7bc)

N-Ethyl-3-carbazolecarboxaldehyde (0.5 mmol), 5o (30 mol %) and K₂CO₃ (1 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 7bc was obtained as a white solid in 88% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.07 (s, 0.03H), 8.57 (s, 1H), 8.13 (d, J=7.8 Hz, 1H), 7.99 (dd, J=8.5, 1.4 Hz, 1H), 7.56-7.51 (m, 1H), 7.51-7.42 (m, 2H), 7.35-7.30 (m, 1H), 4.36 (q, J=7.2 Hz, 2H), 1.44 (t, J=7.3 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 191.6 (t, J=26.1 Hz), 143.6 (s), 140.7 (s), 128.4 (s), 127.2 (s), 126.8 (s), 124.0 (s), 123.1 (s), 123.1 (s), 120.8 (s), 120.3 (s), 109.2 (s), 108.7 (s), 37.9 (s), 13.9 (s); HRMS (EI): m/z caled for C₁₅H₁₂DNO [(M)⁺]: 224.1060, found: 224.1062.

N-(2-(Diethylamino)ethyl)-5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxamide-α-d₁ (7bd)

N-(2-(Diethylamino)ethyl)-5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxamide (0.5 mmol), 5m (30 mol %) and K₂CO₃ (1.5 mmol, 3 equiv) was dissolved in a mixture of D₂O (2 mL) and DCM (0.5 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 7be was obtained as a yellow solid in 88% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.47 (s, 1H), 9.49 (s, 0.02H), 6.94 (s, 1H), 3.54-3.58 (m, 2H), 2.84 (s, 2H), 2.77 (q, J=7.0 Hz, 4H), 2.52 (s, 3H), 2.49 (s, 3H), 1.11 (t, J=7.0 Hz, 6H); ¹³C NMR (100 MHz, DMSO-d₆) δ 177.5-176.8 (m), 164.7 (s), 138.2 (s), 130.8 (t, J=13.7 Hz), 127.7 (s), 118.8 (s), 50.6 (s), 46.7 (s), 35.1 (s), 12.6 (s), 9.7 (s). HRMS (EI): m/z caled for C₁₄H₂₂DN₃O₂[(M)⁺]: 266.1853, found: 266.1854.

4-(4-Formylphenyl)-1,4-dihydro-2,6-dimethyl-,3,5-diethyl ester-α-d₁ (7be)

4-(4-Formylphenyl)-1,4-dihydro-2,6-dimethyl-,3,5-diethyl ester 6be (0.25 mmol), 5o (20 mol %) and K₂CO₃ (0.5 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 ml). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7be was obtained as a yellow solid in 73% yield with 96% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.92 (s, 0.04H), 7.73 (d, J=8.2 Hz, 2H), 7.46 (d, J=8.2 Hz, 2H), 6.35-6.32 (m, 1H), 5.06 (s, 1H), 4.11-4.02 (m, 4H), 2.32 (s, 6H), 1.20 (t, J=7.1 Hz, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 192.2 (t, J=29.4 Hz), 167.4 (s), 155.1 (s), 144.9 (s), 134.4 (s), 129.7 (s), 128.8 (s), 103.1 (s), 59.9 (s), 40.3 (s), 19.4 (s), 14.3 (s); HRMS (ESI): m/z caled for C₂₂H₂₃DNO₅ [(M+H)⁺]: 359.1717, found: 359.1717.

4-(4-(2-(Dimethylamino)-1-(1-hydroxycyclohexyl)ethyl)phenoxy)benzaldehyde-α-d₁ (7bf)

4-(4-(2-(Dimethylamino)-1-(1-hydroxycyclohexyl)ethyl)phenoxy)benzaldehyde 6bf (0.1 mmol), 5m (15 mol %) and K₂CO₃ (0.1 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7bf was obtained as a yellow oil in 55% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.89 (s, 0.02H), 7.83 (d, J=8.6 Hz, 2H), 7.22 (d, J=8.5 Hz, 2H), 7.05 (d, J=8.6 Hz, 2H), 7.00 (d, J=8.5 Hz, 2H), 3.81 (dd, J=12.4, 6.6 Hz, 1H), 3.28 (t, J=5.8 Hz, 1H), 2.95 (d, J=8.3 Hz, 1H), 2.62 (s, 6H), 1.73-0.81 (m, 10H); ¹³C NMR (100 MHz, CDCl₃) δ 190.5 (t, J=26.4 Hz), 162.7 (s), 154.4 (s), 136.2 (s), 132.0 (s), 131.4 (s), 130.9 (s), 120.1 (s), 117.9 (s), 73.7 (s), 60.5 (s), 52.4 (s), 44.5 (s), 37.2 (s), 31.5 (s), 25.5 (s), 21.5 (s), 21.3 (s); HRMS (ESI): m/z caled for C₂₃H₂₉DNO₃ [(M+H)⁺]: 369.2288, found: 369.2289.

2-(2-(2-(4-((4-Chlorophenyl)(phenyl)methyl)piperazin-1-yl)ethoxy)ethoxy)benzaldehyde-α-d₁ (7bg)

2-(2-(2-(4-((4-Chlorophenyl)(phenyl)methyl)piperazin-1-yl)ethoxy)ethoxy)benzaldehyde 6bg (0.1 mmol), 5ag (15 mol %) and AcOK (0.1 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7bg was obtained as a yellow oil in 52% yield with 96% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 10.51 (s, 0.04H), 7.84 (dd, J=7.7, 1.7 Hz, 1H), 7.58-7.52 (m, 1H), 7.37 (dd, J=7.8, 3.7 Hz, 4H), 7.31-7.18 (m, 5H), 7.04 (t, J=7.5 Hz, 1H), 6.99 (d, J=8.4 Hz, 1H), 4.25 (d, J=5.5 Hz, 1H), 4.24 (t, J=2.0 Hz, 2H), 3.88 (t, J=4.8 Hz, 2H), 3.79 (s, 2H), 2.76-2.43 (m, 10H); ¹³C NMR (100 MHz, CDCl₃) δ 189.4 (t, J=29.5 Hz), 161.1 (s), 141.7 (s), 140.9 (s), 135.9 (s), 132.8 (s), 129.1 (s), 128.8 (s), 128.8 (s), 128.5 (s), 127.7 (s), 127.4 (s), 125.0 (s), 121.1 (s), 112.8 (s), 75.1 (s), 69.4 (s), 68.1 (s), 68.0 (s), 57.4 (s), 53.7 (s), 50.5 (s); HRMS (ESI): m/z caled for C₂₈H₃₁DClN₂O₃[(M+H)⁺]: 480.2164, found: 480.2162.

3-Formyl rifamycin-α-d₁ (7bh)

3-Formyl rifamycin (0.05 mmol), 5l (20 mol %) and KOAc (0.1 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7bh was obtained as a red solid in 60% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 13.75 (s, 1H), 13.19 (s, 1H), 12.66 (s, 1H), 12.33 (s, 1H), 10.67 (s, 0.03H), 6.62-6.49 (m, 2H), 6.24 (d, J=12.7 Hz, 1H), 6.07 (dd, J=15.0, 5.0 Hz, 1H), 5.16-5.09 (m, 1H), 4.94 (d, J=10.6 Hz, 1H), 3.78 (d, J=9.6 Hz, 1H), 3.62 (d, J=4.8 Hz, 1H), 3.52-3.48 (m, 2H), 3.05 (s, 4H), 2.45-2.39 (m, 1H), 2.27 (s, 3H), 2.08 (s, 3H), 2.06 (s, 3H), 1.82 (s, 3H), 1.76-1.79 (m, 1H), 1.55 (dd, J=9.8, 7.2 Hz, 1H), 1.36-1.41 (m, 1H), 1.03 (d, J=7.0 Hz, 3H), 0.91 (d, J=7.0 Hz, 3H), 0.67 (d, J=6.9 Hz, 3H), −0.29 (d, J=6.9 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.6 (s), 192.9-192.5 (m), 173.3 (s), 171.1 (s), 169.4 (s), 167.5 (s), 155.5 (s), 142.7 (s), 141.8 (s), 136.7 (s), 135.9 (s), 126.8 (s), 121.5 (s), 119.6 (s), 118.4 (s), 117.9 (s), 116.3 (s), 109.8 (s), 108.5 (s), 108.2 (s), 104.5 (s), 75.9 (s), 75.5 (s), 73.2 (s), 69.6 (s), 56.1 (s), 38.6 (s), 37.6 (s), 36.6 (s), 32.2 (s), 20.5 (s), 19.7 (s), 19.6 (s), 15.9 (s), 9.8 (s), 8.1 (s), 7.6 (s), 6.8 (s); HRMS (ESI): m/z caled for C₃₈H₄₆DNNaO₁₃ [(M+Na)⁺]: 749.3008, found: 749.3009.

2′-(2H-Tetrazol-5-yl)biphenyl-4-yl)methyl)-2-butyl-4-chloro-1H-imidazole-5-carbaldehyde-α-d₁ (7bi)

2′-(2H-Tetrazol-5-yl)biphenyl-4-yl)methyl)-2-butyl-4-chloro-1H-imidazole-5-carbaldehyde (0.1 mmol), 5l (20 mol %) and KOAc (0.2 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 7bi was obtained as a white solid in 53% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.62 (s, 0.01H), 7.82 (d, J=7.6 Hz, 1H), 7.56 (t, J=7.2 Hz, 1H), 7.47 (t, J=7.2 Hz, 1H), 7.38 (d, J=7.6 Hz, 1H), 7.03 (d, J=8.0 Hz, 2H), 6.92 (d, J=8.0 Hz, 2H), 5.47 (s, 2H), 2.56 (t, J=7.6 Hz, 2H), 1.63-1.55 (m, 2H), 1.34-1.24 (m, 2H), 0.83 (t, J=7.3 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 178.2-177.4 (m), 155.3 (s), 154.9 (s), 143.2 (s), 140.7 (s), 139.2 (s), 135.3 (s), 131.3 (s), 130.8 (s), 129.6 (s), 128.2 (s), 126.7 (s), 124.1 (s), 122.9 (s), 48.0 (s), 29.2 (s), 26.4 (s), 22.3 (s), 13.7 (s); HRMS (ESI): m/z caled for C₂₂H₂₁DClN₆O [(M+H)⁺]: 422.1606, found: 422.1605.

(E)-Cinnamaldehyde-α-d₁ (10a)

(E)-Cinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10a was obtained as a yellow oil in 63% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.71 (d, J=7.7 Hz, 0.03H), 7.59-7.56 (m, 2H), 7.48 (d, J=16.0 Hz, 1H), 7.46-7.40 (m, 3H), 6.72 (d, J=16.0 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 193.5 (t, J=26.3), 152.8 (s), 134.0 (s), 131.3 (s), 129.1 (s), 128.5 (s), 127.2 (s); HRMS (EI): m/z caled for C₉H₇DO [(M)⁺]: 133.0638, found: 133.0639.

(E)-4-Acetoxy-3-methoxycinnamaldehyde-α-d₁ (10b)

(E)-4-Acetoxy-3-methoxycinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10b was obtained as a brown solid in 40% yield with 95% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.69 (d, J=7.7 Hz, 0.05H), 7.44 (d, J=15.9 Hz, 1H), 7.18-7.12 (m, 2H), 7.09 (d, J=8.1 Hz, 1H), 6.66 (d, J=15.9 Hz, 1H), 3.87 (s, 3H), 2.33 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 193.2 (t, J=26.2 Hz), 168.7 (s), 151.9 (s), 151.6 (s), 142.2 (s), 133.0 (s), 128.7 (t, J=3.6 Hz), 123.5 (s), 121.9 (s), 111.4 (s), 56.0 (d, J=2.9 Hz), 20.7 (d, J=2.1 Hz); HRMS (EI): m/z caled for C12H₁₁DO₄ [(M)⁺]: 221.0798, found: 221.0780.

(E)-4-Chlorocinnamaldehyde-α-d₁ (10c)

(E)-4-Chlorocinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 10c was obtained as a yellow solid in 40% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.70 (d, J=7.6 Hz, 0.03H), 7.50 (d, J=8.5 Hz, 2H), 7.43 (d, J=12.3 Hz, 1H), 7.40 (d, J=8.5 Hz, 2H), 6.68 (d, J=16.0 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 193.2 (t, J=26.4 Hz), 151.1 (s), 137.3 (s), 132.5 (s), 129.6 (s), 129.5 (s), 128.9 (t, J=3.8 Hz); HRMS (EI): m/z caled for C₉H₆DClO [(M)⁺]: 167.0248, found: 167.0246.

(E)-4-Bromocinnamaldehyde-α-d₁ (10d)

(E)-4-Bromocinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10d was obtained as a brown solid in 33% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.70 (d, J=7.1 Hz, 0.03H), 7.58 (d, J=8.2 Hz, 2H), 7.45-7.37 (m, 3H), 6.70 (d, J=16.0 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 193.1 (t, J=27.2 Hz), 151.1 (s), 132.9 (s), 132.4 (s), 129.8 (s), 129.0 (s), 125.7 (s); HRMS (EI): m/z caled for C₉H₆DBrO [(M)⁺]: 210.9743, found: 210.9744.

(E)-4-Methoxycinnamaldehyde-α-d₁ (10e)

(E)-4-Methoxycinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10e was obtained yellow oil in 41% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.65 (d, J=7.8 Hz, 0.01H), 7.52 (d, J=8.8 Hz, 2H), 7.42 (d, J=15.9 Hz, 1H), 6.94 (d, J=8.8 Hz, 2H), 6.61 (d, J=15.9 Hz, 1H), 3.86 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 193.5 (t, J=26.1 Hz), 162.2 (s), 152.7 (s), 130.4 (s), 126.8 (s), 126.5 (t, J=3.7 Hz), 114.6 (s), 55.5 (d, J=4.2 Hz); HRMS (EI): m/z caled for C₁₀H₉DO₂ [(M)⁺]: 163.0744, found: 163.0743.

(E)-4-Methylcinnamaldehyde-α-d₁ (10f)

(E)-4-Methylcinnamaldehyde (0.25 mmol), 5p (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10f was obtained as a yellow oil in 57% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.68 (d, J=7.8 Hz, 0.02H), 7.48-7.43 (m, 3H), 7.24 (d, J=8.0 Hz, 2H), 6.68 (d, J=15.9 Hz, 1H), 2.39 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 193.6 (t, J=26.2 Hz), 153.0 (s), 142.0 (s), 131.3 (s), 129.9 (s), 128.6 (s), 127.7 (t, J=3.8 Hz), 21.6 (d, J=1.7 Hz); HRMS (EI): m/z caled for C₁₀H₉DO [(M)⁺]: 147.0794, found: 147.0795.

alpha-Methylcinnamaldehyde-α-d₁ (10g)

alpha-Methylcinnamaldehyde (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 10g was obtained as a colorless oil in 95% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.48 (s, 0.02H), 7.43 (d, J=7.4 Hz, 2H), 7.38-7.27 (m, 3H), 7.16 (s, 1H), 1.98 (d, J=1.3 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.2 (t, J=26.5 Hz), 149.8 (s), 138.3 (t, J=3.5 Hz), 135.2 (s), 130.1 (s), 129.6 (s), 128.7 (s), 10.9 (s); HRMS (EI): m/z caled for C₁₀H₉DO [(M)⁺]: 147.0794, found: 147.0795.

(E)-2-Methyl-3-(3-nitrophenyl)acrylaldehyde-α-d₁ (10h)

(E)-2-Methyl-3-(3-nitrophenyl)acrylaldehyde (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10h was obtained as a white solid in 41% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.64 (s, 0.01H), 8.37 (t, J=1.7 Hz, 1H), 8.27-8.23 (m, 1H), 7.83 (d, J=7.8 Hz, 1H), 7.65 (t, J=8.0 Hz, 1H), 7.32 (s, 1H), 2.10 (d, J=1.4 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 194.4 (t, J=26.7 Hz), 148.5 (s), 146.0 (s), 140.6 (t, J=3.6 Hz), 136.7 (s), 135.3 (s), 129.8 (s), 124.3 (s), 123.9 (s), 10.9 (s); HRMS (EI): m/z caled for C₁₀H₈DNO₃ [(M)⁺]: 192.0645, found: 192.0646.

(E)-4-Methoxy-2-methylcinamaldehyde-α-d₁ (10i)

(E)-4-Methoxy-2-methylcinamaldehyde (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10i was obtained as a yellow oil in 73% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.53 (s, 0.02H), 7.52 (d, J=8.8 Hz, 2H), 7.19 (s, 1H), 6.97 (d, J=8.8 Hz, 2H), 3.85 (s, 3H), 2.07 (d, J=1.2 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.2 (t, J=26.4 Hz), 160.8 (s), 149.9 (s), 136.1 (t, J=3.5 Hz), 132.1 (s), 128.0 (s), 114.2 (s), 55.4 (d, J=2.7 Hz), 10.9 (s); HRMS (EI): m/z caled for C₁₁H₁₁DO₂ [(M)⁺]: 177.0900, found: 177.0901.

(E)-2-Methyl-3-(naphthalen-2-yl)acrylaldehyde-α-d₁ (10j)

(E)-2-Methyl-3-(naphthalen-2-yl)acrylaldehyde (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10j was obtained as a white solid in 85% yield with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.64 (s, 0.01H), 7.99 (s, 1H), 7.90-7.84 (m, 3H), 7.62 (dd, J=8.6, 1.6 Hz, 1H), 7.58-7.51 (m, 2H), 7.39 (s, 1H), 2.18 (d, J=1.3 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.2 (t, J=26.5 Hz), 149.8 (s), 138.4 (t, J=3.5 Hz), 133.5 (s), 133.1 (s), 132.7 (s), 130.4 (s), 128.7 (s), 128.4 (s), 127.8 (s), 127.4 (s), 126.8 (s), 126.8 (s), 11.1 (s); HRMS (EI): m/z caled for C₁₄H₁₁DO [(M)⁺]: 197.0951, found: 197.0952.

2-Methyl-3-(2-furyl)propenal-α-d₁ (10k)

2-Methyl-3-(2-furyl)propenal (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 10k was obtained as a yellow oil in 75% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.46 (s, 0.03H), 7.59 (d, J=1.6 Hz, 1H), 7.00 (s, 1H), 6.75 (d, J=3.5 Hz, 1H), 6.54 (dd, J=3.5, 1.8 Hz, 1H), 2.07 (d, J=1.1 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 193.9 (t, J=26.5 Hz), 151.6 (s), 145.3 (s), 135.4 (s), 134.9 (t, J=3.6 Hz), 116.5 (s), 112.7 (s), 10.5 (s); HRMS (EI): m/z caled for C₈H₇DO₂ [(M)⁺]: 137.0587, found: 137.0589.

α-Amylcinnamaldehyde-α-d₁ (10l)

α-Amylcinnamaldehyde (0.25 mmol), 5l (20 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 10l was obtained as a colorless oil in 96% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.54 (s, 0.03H), 7.51-7.36 (m, 5H), 7.19 (s, 1H), 2.54-2.50 (m, 2H), 1.54-1.45 (m, 2H), 1.39-1.30 (m, 4H), 0.89 (t, J=7.1 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.3 (t, J=26.4 Hz), 149.7 (s), 143.3 (t, J=3.2 Hz), 135.0 (s), 129.7 (s), 129.5 (s), 128.8 (s), 32.1 (s), 28.0 (s), 24.7 (s), 22.4 (s), 14.0 (s); HRMS (EI): m/z caled for C₁₄H₁₇DO [(M)⁺]: 203.1420, found: 203.1421.

α-Hexylcinnamaldehyde-α-d₁ (10m)

α-Hexylcinnamaldehyde (0.25 mmol), 5l (20 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 10m was obtained as a colorless oil in 92% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.54 (s, 0.03H), 7.51-7.36 (m, 5H), 7.20 (s, 1H), 2.55-2.51 (m, 2H), 1.53-1.44 (m, 2H), 1.42-1.25 (m, 6H), 0.88 (t, J=6.8 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 195.3 (t, J=26.4), 149.7 (s), 143.3 (t, J=2.9 Hz), 135.0 (s), 129.7 (s), 129.5 (s), 128.8 (s), 31.5 (s), 29.6 (s), 28.3 (s), 24.8 (s), 22.6 (s), 14.1 (s); HRMS (EI): m/z caled for C₁₅H₁₉DO [(M)⁺]: 217.1577, found: 217.1578.

(E)-Dimethyl 2-(3-oxo-1-phenylprop-1-en-2-yl)malonate-α-d₁ (10n)

(E)-Dimethyl 2-(3-oxo-1-phenylprop-1-en-2-yl)malonate (0.25 mmol), 5l (20 mol %), and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10n was obtained as a yellow oil in 61% yield with 95% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.61 (s, 0.05H), 7.65 (s, 1H), 7.47-7.41 (m, 5H), 4.75 (s, 1H), 3.70 (s, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 192.3 (t, J=27.0 Hz), 167.6 (s), 152.7 (s), 135.0 (t, J=3.0 Hz), 133.4 (s), 130.4 (s), 129.2 (s), 129.0 (s), 52.9 (d, J=1.7 Hz), 49.1 (s); HRMS (EI): m/z caled for C₁₄H₁₃DO₅ [(M)⁺]: 263.0904, found: 263.0903.

5-Methyl-2-phenyl-2-hexenal-α-d₁ (100)

5-Methyl-2-phenyl-2-hexenal (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 10o was obtained as a colorless oil in 80% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.64 (s, 0.02H), 7.46-7.38 (m, 2H), 7.37-7.31 (m, 1H), 7.18-7.14 (m, 2H), 6.77 (t, J=7.5 Hz, 1H), 2.30-2.24 (m, 2H), 1.90-1.78 (m, 1H), 0.93 (d, J=6.7 Hz, 6H); ¹³C NMR (100 MHz, CDCl₃) δ 193.4 (t, J=26.6 Hz), 155.6 (s), 144.6 (t, J=3.4 Hz), 132.8 (s), 129.5 (s), 128.2 (s), 127.9 (s), 38.6 (s), 28.5 (s), 22.5 (s); HRMS (EI): m/z caled for C₁₃H₁₅DO [(M)⁺]: 189.1264, found: 189.1265.

(−)-Perillaldehyde-α-d₁ (10p)

(−)-Perialdehyde (0.25 mmol), 5l (20 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 10p was obtained as a colorless oil in 75% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.41 (s, 0.02H), 6.82-6.78 (m, 1H), 4.75 (s, 1H), 4.70 (s, 1H), 2.49-2.37 (m, 2H), 2.27-2.16 (m, 2H), 2.15-2.05 (m, 1H), 1.91-1.86 (m, 1H), 1.73 (s, 3H), 1.48-1.38 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 193.6 (t, J=26.2 Hz), 150.6 (s), 148.3 (s), 141.2 (t, J=3.5 Hz), 109.5 (s), 40.7 (s), 31.7 (s), 26.3 (s), 21.5 (s), 20.7 (s); HRMS (EI): m/z caled for C₁₀H₁₃DO [(M)⁺]: 151.1107, found: 151.1109.

(1R)-Myrtenal-α-d₁ (10q)

(1R)-Myrtenal (0.25 mmol), 5l (20 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10q was obtained as a colorless oil in 67% yield with 97% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.41 (s, 0.03H), 6.72-6.67 (m, 1H), 2.84 (t, J=5.6 Hz, 1H), 2.65-2.43 (m, 3H), 2.19-2.14 (m, 1H), 1.31 (s, 3H), 1.03 (d, J=9.2 Hz, 1H), 0.72 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 190.9 (t, J=26.3 Hz), 151.5 (t, J=3.6 Hz), 147.7 (s), 40.7 (s), 38.0 (s), 37.6 (s), 33.0 (s), 31.1 (s), 25.7 (s), 20.9 (s); HRMS (EI): m/z caled for C₁₀H₁₃DO [(M)⁺]: 151.1107, found: 151.1109.

2-Benzylacrylaldehyde-α-d₁ (10r)

2-Benzylacrylaldehyde (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 10r was obtained as a yellow oil in 50% yield with 96% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.61 (s, 0.04H), 7.33-7.17 (m, 5H), 6.11 (s, 1H), 6.07 (s, 1H), 3.57 (s, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 193.7 (t, J=26.7 Hz), 149.7 (t, J=3.7 Hz), 138.2 (s), 135.2 (s), 129.2 (s), 128.6 (s), 126.5 (s), 34.1 (s); HRMS (EI): m/z caled for C₁₀H₉DO [(M)⁺]: 147.0794, found: 147.0796.

2-Methylene-3-(5-methylfuran-2-yl)butanal-α-d₁ (10s)

2-Methylene-3-(5-methylfuran-2-yl)butanal (0.25 mmol), 5l (10 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10s was obtained as a yellow oil in 50% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.57 (s, 0.02H), 6.18 (d, J=0.6 Hz, 1H), 6.05 (s, 1H), 5.94 (d, J=2.9 Hz, 1H), 5.86 (dd, J=2.9, 0.9 Hz, 1H), 4.04 (q, J=7.1 Hz, 1H), 2.23 (s, 3H), 1.37 (d, J=7.2 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 193.2 (t, J=26.7 Hz), 154.8 (s), 152.5 (t, J=3.7 Hz), 151.0 (s), 134.3 (s), 106.2 (s), 105.8 (s), 31.2 (s), 18.3 (s), 13.5 (s); HRMS (EI): m/z caled for C₁₀H₁₁DO₂ [(M)⁺]: 165.0900, found: 165.0902.

Benzyl (2-formylallyl)carbamate-α-d₁ (10t)

Benzyl (2-formylallyl)carbamate (0.25 mmol), 5l (20 mol %) and KOAc (0.25 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 10t was obtained as a yellow solid in 42% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.57 (s, 0.02H), 7.38-7.30 (m, 5H), 6.43 (s, 1H), 6.11 (s, 1H), 5.23 (s, 1H), 5.09 (s, 2H), 4.00 (d, J=6.3 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 193.8 (s), 156.3 (s), 146.0 (s), 136.3 (s), 135.0 (s), 128.6 (s), 128.2 (s), 128.1 (s), 66.9 (s), 39.3 (s); HRMS (EI): m/z caled for C₁₂H₁₂DNO₃ [(M)⁺]: 220.0958, found: 220.0959.

Phenylacetaldehyde-1,2-d₁,d₂ (12a)

Phenylacetaldehyde (0.5 mmol), 5q (20 mol %) and KOAc (1.0 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12a was obtained as a colorless oil in 48% yield with 98% D-incorporation at position 1 and 94% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.75 (s, 0.02H), 7.38 (t, J=7.2 Hz, 2H), 7.34-7.29 (m, 1H), 7.25-7.21 (m, 2H), 3.68-3.66 (m, 0.12H); ¹³C NMR (100 MHz, CDCl₃) δ 199.3 (t, J=26.9 Hz), 131.8 (s), 129.6 (s), 129.0 (s), 127.4 (s), 49.9 (d, J=12.6 Hz) HRMS (EI): m/z caled for C₈H₅D₃O [(M)⁺]: 123.0763, found: 123.0764.

3-Phenylpropionaldehyde-1,2,3-d₁,d₂,d₂ (12b)

3-Phenylpropionaldehyde (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12b was obtained as a colorless oil in 51% yield with 98% D-incorporation at position 1, 41% D-incorporation at position 2 and 16% D-incorporation at position 3. ¹H NMR (400 MHz, CDCl₃) δ 9.83 (d, J=1.2 Hz, 0.02H), 7.34 (t, J=7.3 Hz, 2H), 7.29-7.21 (m, 3H), 2.99 (t, J=7.4 Hz, 1.67H), 2.83-2.75 (m, 1.18H); ¹³C NMR (100 MHz, CDCl₃) δ 201.3 (t, J=26.2 Hz), 140.5 (s), 128.7 (s), 128.4 (s), 126.3 (s), 45.1 (t, J=3.7 Hz), 28.1 (d, J=5.7 Hz); HRMS (EI): m/z caled for C₉H₉DO [(M)⁺]: 135.0794, Found: 135.0799; C₉H₈D₂O [(M)⁺]: 136.0857, found: 136.0858; C₉H₅D₅O [(M)⁺]: 139.1045, found: 139.1049.

Benzenebutanal-1,2,3-d₁,d₂,d₂ (12c)

Benzenebutanal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12c was obtained as a colorless oil in 67% yield with 99% D-incorporation at position 1, 95% D-incorporation at position 2 and 16% D-incorporation at position 3. ¹H NMR (400 MHz, CDCl₃) δ 9.76 (s, 0.01H), 7.30 (t, J=7.3 Hz, 2H), 7.24-7.16 (m, 3H), 2.67 (t, J=7.5 Hz, 2H), 2.45-2.42 (m, 0.09H), 1.96 (t, J=7.5 Hz, 1.68H); ¹³C NMR (100 MHz, CDCl₃) δ 202.2 (t, J=25.8 Hz), 141.3 (s), 128.5 (s), 126.1 (s), 42.2 (s), 34.9 (d, J=9.1 Hz), 23.5 (s); HRMS (EI): m/z caled for C₁₀H₉D₃O [(M)⁺]: 151.1076, Found: 151.1090; C₁₀H₈D₄O [(M)⁺]: 152.1139, Found: 152.1140; C₁₀H₇D₅O [(M)⁺]: 153.1202, found: 153.1190.

3-Thienylpropionaldehyde-1,2-d₁,d₂ (12d)

3-Thienylpropionaldehyde (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12d was obtained as a colorless oil in 69% yield with 98% D-incorporation at position 1, 21% D-incorporation at position 2 and 7% D-incorporation at position 3. ¹H NMR (400 MHz, CDCl₃) δ 9.82 (s, 0.02H), 7.13 (dd, J=5.1, 1.1 Hz, 1H), 6.92 (dd, J=5.1, 3.5 Hz, 1H), 6.82 (d, J=3.3 Hz, 1H), 3.18 (t, J=7.2 Hz, 1.86H), 2.84 (t, J=7.3 Hz, 1.50H); ¹³C NMR (100 MHz, CDCl₃) δ 200.7 (t, J=26.4), 143.0 (s), 127.0 (s), 124.8 (s), 123.6 (s), 45.2 (t, J=3.7), 22.3 (d, J=6.0 Hz); HRMS (EI): m/z caled for C₇H₇DOS [(M)⁺]: 141.0359, found: 141.0360.

3-(1-Methyl-1H-3-indolyl)propanal-1,2,3-d₁,d₂,d₂ (12e)

3-(1-Methyl-1H-3-indolyl)propanal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12e was obtained as a yellow solid in 48% yield with 95% D-incorporation at position 1, 93% D-incorporation at position 2 and 79% D-incorporation at position 3. ¹H NMR (400 MHz, CDCl₃) δ 9.80 (s, 0.05H), 7.55 (d, J=7.9 Hz, 1H), 7.27 (d, J=8.2 Hz, 1H), 7.22 (dd, J=7.8, 7.2 Hz, 1H), 7.13-7.07 (m, 1H), 6.81 (s, 1H), 3.70 (s, 3H), 3.06 (t, J=6.5 Hz, 0.43H), 2.80-2.75 (m, 0.14H); ¹³C NMR (100 MHz, CDCl₃) δ 202.6 (t, J=26.2 Hz), 137.1 (s), 127.5 (s), 126.4 (s), 121.8 (s), 118.9 (s), 118.7 (s), 113.0 (s), 109.3 (s), 43.4 (s), 32.6 (s), 17.7 (s); HRMS (EI): m/z caled for C₁₂H₈D₅NO [(M)⁺]: 192.1311, found: 192.1310.

3-(5-Methyl-2-furanyl)butanal-1,2-d₁,d₂ (12f)

3-(5-Methyl-2-furanyl)butanal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12f was obtained as a colorless oil in 73% yield with 97% D-incorporation at position 1, 71% D-incorporation at position 2 and 78% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.75 (s, 0.03H), 5.86 (d, J=2.9 Hz, 1H), 5.84 (s, 1H), 3.39-3.32 (m, 1H), 2.78-2.72 (m, 0.32H), 2.57-2.51 (m, 0.24H), 2.23 (s, 3H), 1.28 (d, J=7.0 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 201.9-201.1 (m), 156.4 (s), 150.8 (s), 105.8 (s), 104.8 (s), 49.2-45.8 (m), 27.8 (d, J=5.1 Hz), 19.0 (s), 13.5 (d, J=1.3 Hz); HRMS (EI): m/z caled for C₉H₉D₃O₂: 155.1026, found: 155.1028.

Octanal-1,2,3-d₁,d₂,d₂ (12g)

Octanal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12g was obtained as a colorless oil in 71% yield with 96% D-incorporation at position 1, 95% D-incorporation at position 2 and 23% D-incorporation at position 3. ¹H NMR (400 MHz, CDCl₃) δ 9.74 (s, 0.04H), 2.41-2.20 (m, 0.1H), 1.58 (d, J=6.5 Hz, 1.54H), 1.35-1.22 (m, 8H), 0.86 (dd, J=8.8, 4.9 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 202.9 (t, J=26.6 Hz), 43.1 (m), 31.6 (s), 29.1 (s), 29.0 (s), 22.6 (s), 21.9 (s), 14.0 (s); HRMS (EI): m/z caled for C₈H₁₃D₃O [(M)⁺]: 131.1389, found: 131.1385.

6-Heptynal-1,2-d₁,d₂ (12h)

6-Heptynal (0.5 mmol), 5t (10 mol %), NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. 12h was obtained as a colorless oil in 64% yield with 98% D-incorporation at position 1, 89% D-incorporation at position 2, 16% D-incorporation at position 3 and 23% D-incorporation at position 4. ¹H NMR (400 MHz, CDCl₃) δ 9.77 (s, 0.02H), 2.48-2.41 (m, 0.21H), 2.26-2.18 (m, 2H), 1.95 (t, J=2.6 Hz, 0.64H), 1.78-1.70 (m, 1.74H), 1.61-1.52 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 202.1 (t, J=23.5 Hz), 83.8 (s), 68.8 (s), 27.7 (s), 22.7 (s), 20.9 (s), 18.2 (s); HRMS (EI): m/z caled for C₇H₉DO [(M)⁺]: 111.0794, Found: 111.0793; C₇H₇D₃O [(M)⁺]: 113.0920, found: 113.0922.

Cis-6-Nonenal-1,2-d₁,d₂ (12i)

Cis-6-Nonenal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 12i was obtained as a colorless oil in 72% yield with 96% D-incorporation at position 1 and 73% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.75 (s, 0.04H), 5.41-5.34 (m, 1H), 5.33-5.26 (m, 1H), 2.42 (t, J=7.4 Hz, 0.5H), 2.09-1.96 (m, 4H), 1.67-1.58 (m, 2H), 1.42-1.33 (m, 2H), 0.94 (t, J=7.5 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 202.6 (d, J=52.2 Hz), 132.2 (s), 128.4 (s), 43.6 (s), 29.1 (t, J=7.6 Hz), 26.8 (s), 21.6-21.4 (m), 20.5 (s), 14.3 (s); HRMS (EI): m/z caled for C₉H₁₄D₂O [(M)⁺]: 142.1327, Found: 142.1322; C₉H₁₃D₃O [(M)⁺]: 143.1389, found: 143.1393.

Citronellal-1,2-d₁,d₂ (12j)

Citronellal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 12j was obtained as a colorless oil in 78% yield with 96% D-incorporation at position 1, 50% D-incorporation at position 2 and 50% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.74 (s, 0.04H), 5.10-5.04 (m, 1H), 2.38 (dd, J=15.9, 5.5 Hz, 0.50H), 2.21 (dd, J=16.1, 8.0 Hz, 0.50H), 2.07-1.92 (m, 3H), 1.67 (s, 3H), 1.59 (s, 3H), 1.40-1.21 (m, 2H), 0.96 (d, J=6.7 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃) δ 202.8 (t, J=25.8 Hz), 131.8 (s), 124.0 (s), 50.8 (t, J=3.5 Hz), 36.9 (d, J=4.3 Hz), 27.7 (d, J=9.8 Hz), 25.7 (s), 25.4 (s), 19.8 (d, J=6.5 Hz), 17.7 (s); HRMS (EI): m/z caled for C₁₀H₁₇DO [(M)⁺]: 155.1420, Found: 155.1424; C₁₀H₁₆D₂O [(M)⁺]: 156.1483, Found: 156.1474; C₁₀H₁₅D₃O [(M)⁺]: 157.1546, found: 157.1547.

Benzyl-4-oxobutanoate-1,2-d₁,d₂ (12k)

Benzyl-4-oxobutanoate (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv), was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 12k was obtained yellow solid in 55% yield with 99% D-incorporation at position 1 and 96% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.79 (s, 0.01H), 7.38-7.31 (m, 5H), 5.22 (s, 1H), 5.07 (s, 2H), 3.47 (d, J=6.1 Hz, 2H), 2.69 (s, 0.07H). ¹³C NMR (100 MHz, CDCl₃) δ 201.4-200.7 (m), 156.4 (s), 136.4 (s), 128.6 (s), 128.2 (s), 128.1 (s), 66.8 (s), 43.4 (s), 34.4 (s), 29.7 (s); HRMS (EI): m/z caled for C₁₁H₁₀D₃NO₃ [(M)⁺]: 210.1084, found: 210.1085.

2-Phenylpropionaldehyde-1,2-d₁,d₁ (12l)

2-Phenylpropionaldehyde (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12l was obtained as a colorless oil in 73% yield with 99% D-incorporation at position 1 and 97% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.69 (s, 0.01H), 7.41-7.30 (m, 3H), 7.23-7.20 (m, 2H), 3.63 (q, J=7.0 Hz, 0.03H), 1.45 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 200.9 (t, J=26.6 Hz), 137.7 (s), 129.1 (s), 128.3 (s), 127.6 (s), 52.7-52.1 (m), 14.5 (s); HRMS (EI): m/z caled for C₉H₈D₂O [(M)⁺]: 136.0857, found: 136.0856.

2-Methyl-3-phenylpropionaldehyde-1,2-d₁,d₁ (12m)

2-Methyl-3-phenylpropionaldehyde (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12m was obtained as a colorless oil in 82% yield with 98% D-incorporation at position 1 and 60% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.73 (d, J=1.3 Hz, 0.02H), 7.34-7.28 (m, 2H), 7.25-7.16 (m, 3H), 3.12-3.06 (m, 1H), 2.72-2.65 (m, 0.4H), 2.65-2.58 (m, 1H), 1.10 (d, J=6.8 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 204.1 (td, J=25.8, 9.1 Hz), 138.9 (d, J=1.2 Hz), 129.1 (s), 128.6 (s), 126.4 (s), 47.9 (t, J=3.5 Hz), 36.6 (d, J=6.8 Hz), 13.2 (d, J=7.5 Hz); HRMS (EI): m/z caled for C₁₀H₁₀D₂O [(M)⁺]: 150.1014, found: 150.1018.

2-Methyl-5-oxo-5-phenylpentanal-1,2,4-d₁,d₁,d₂ (12n)

2-Methyl-5-oxo-5-phenylpentanal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 12n was obtained as a colorless oil in 72% yield with 98% D-incorporation at position 1, 83% D-incorporation at position 2 and 80% D-incorporation at position 4. ¹H NMR (400 MHz, CDCl₃) δ 9.64 (s, 0.02H), 7.93 (d, J=7.1 Hz, 2H), 7.57-7.52 (m, 1H), 7.44 (t, J=7.6 Hz, 2H), 3.04-2.96 (m, 0.40H), 2.50-2.43 (m, 0.17H), 2.11 (dd, J=14.2, 7.0 Hz, 1H), 1.85-1.78 (m, 1H), 1.15 (d, J=7.2 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 204.5-203.9 (m), 199.4 (t, J=6.2 Hz), 136.7 (s), 133.2 (s), 128.6 (s), 128.0 (s), 45.5 (t, J=3.3 Hz), 35.5 (s), 24.6 (s), 13.5 (d, J=7.9 Hz); HRMS (EI): m/z caled for C₁₂H₁₀D₄O₂ [(M)⁺]: 194.1245, found: 194.1275.

2,6-Dimethyl-5-heptenal-1,2-d₁,d₁ (12o)

2,6-Dimethyl-5-heptenal (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 50° C. for 12 hours. 12o was obtained as a colorless oil in 64% yield with 98% D-incorporation at position 1 and 23% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.59 (d, J=1.8 Hz, 0.02H), 5.08-5.04 (m, 1H), 2.43 (t, J=7.4 Hz, 0.24H), 2.36-2.29 (m, 0.57H), 2.23 (dd, J=14.6, 7.3 Hz, 0.25H), 2.01 (dd, J=14.7, 7.4 Hz, 2H), 1.78-1.69 (m, 1H), 1.66 (s, 3H), 1.57 (s, 3H), 1.42-1.33 (m, 1H) 1.07 (d, J=7.0 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 204.9 (t, J=25.8 Hz), 132.7 (s), 123.4 (s), 45.6 (t, J=3.3 Hz), 30.6 (s), 25.7 (s), 25.3 (s), 17.7 (s), 13.2 (s); HRMS (EI): m/z caled for C₉H₁₅DO [(M)⁺]: 141.1264, found: 141.1243.

Cyclohexanaldehyde-1,2-d₁,d₁ (12p)

Cyclohexanaldehyde (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12p was obtained as a colorless oil in 70% yield with 98% D-incorporation at position 1 and 12% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.59 (s, 0.02H), 2.24-2.18 (m, 0.80H), 1.90-1.84 (m, 2H), 1.74-1.70 (m, 2H), 1.65-1.59 (m, 1H), 1.36-1.20 (m, 5H); ¹³C NMR (100 MHz, CDCl₃) δ 204.8 ((t, J=25.8 Hz), 49.8 (t, J=3.3 Hz), 28.8 (s), 25.9 (d, J=2.5 Hz), 25.0 (d, J=2.7 Hz); HRMS (EI): m/z caled for C₇H₁₁DO [(M)⁺]: 113.0951, found C₇H₁₁DO: 113.0952.

1-(tert-Butoxycarbonyl)-4-formylpiperidine-1,2-d₁,d₁ (12q)

1-(tert-butoxycarbonyl)-4-formylpiperidine (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 30° C. for 12 hours. 12q was obtained as a white solid in 76% yield with 99% D-incorporation at position 1, and 45% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.63 (s, 0.01H), 3.95 (d, J=8.2 Hz, 2H), 2.90 (t, J=11.5 Hz, 2H), 2.42-2.35 (m, 0.55H), 1.85 (d, J=10.7 Hz, 2H), 1.57-1.48 (m, 2H), 1.43 (s, 9H); ¹³C NMR (100 MHz, CDCl₃) δ 202.7 (t, J=26.0 Hz), 154.7 (s), 79.7 (s), 47.8 (t, J=3.5 Hz), 42.8 (m), 28.40 (s), 25.1 (d, J=10.1 Hz); HRMS (EI): m/z caled for C₁₁H₁₇D₂NO₃ [(M)⁺]: 215.1490, found: 215.1489.

tert-Butyl N-(1-benzyl-2-oxoethyl)carbamate-1,2-d₁,d₁ (12r)

tert-Butyl N-(1-benzyl-2-oxoethyl)carbamate (0.5 mmol), 5q (10 mol %) and NaHCO₃ (0.5 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 40° C. for 12 hours. Compound 12r was obtained as a colorless oil in 86% yield with 99% D-incorporation at position 1 and 73% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.67 (s, 0.01H), 7.23 (t, J=7.2 Hz, 2H), 7.19-7.16 (m, 1H), 7.10 (d, J=6.9 Hz, 2H), 5.01 (s, 1H), 4.35 (d, J=6.7 Hz, 0.23H), 3.04 (d, J=6.6 Hz, 2H), 1.36 (s, 9H). ¹³C NMR (100 MHz, CDCl₃) δ 199.5-198.8 (m), 155.4 (s), 135.8 (s), 129.3 (s), 128.8 (s), 127.1 (s), 80.2 (s), 60.7 (s), 35.4 (s), 28.3 (s); HRMS (EI): m/z caled for C₁₃H₁₇DNO₂ [(M−CDO)⁺]: 221.1400, found: 221.1401.

2-(1-(4-Chlorobenzoyl)-5-methoxy-2-Methyl-1H-indol-3-yl)acetaldehyde-1,2-d₁,d₂ (12s)

2-(1-(4-Chlorobenzoyl)-5-methoxy-2-Methyl-1H-indol-3-yl)acetaldehyde 1is (0.1 mmol), 5q (20 mol %) and AcOK (0.1 mmol, 1 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 ml) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 12s was obtained as a tan solid in 60% yield with 99% D-incorporation at position 1 and 97% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.71 (s, 0.01H), 7.67 (d, J=8.5 Hz, 2H), 7.48 (d, J=8.4 Hz, 2H), 6.86 (d, J=8.9 Hz, 2H), 6.69 (dd, J=8.9, 2.5 Hz, 1H), 3.83 (s, 3H), 3.70 (s, 0.06H), 2.38 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 198.2-197.5 (m), 168.2 (s), 156.2 (s), 139.5 (s), 136.5 (s), 133.7 (s), 131.2 (s), 130.9 (s), 130.6 (s), 129.2 (s), 115.1 (s), 111.9 (s), 109.9 (s), 100.8 (s), 55.7 (d, J=2.3 Hz), 38.6 (m), 13.4 (s); HRMS (ESI): m/z caled for C₁₉H₁₄D₃ClNO₃ [(M+H)⁺]: 345.1085, found: 345.1089.

2-(1,7-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetaldehyde-1,2-d₁,d₂ (12t)

2-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)acetaldehyde 11t (0.1 mmol), 5q (20 mol %) and AcOK (0.2 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 12t was obtained liquid in 52% yield with 99% D-incorporation at position 1 and 97% D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.77 (s, 0.01H), 8.52 (s, 1H), 7.41 (d, J=7.7 Hz, 1H), 7.13 (t, J=7.5 Hz, 1H), 7.07 d, J=6.8 Hz, 1H), 4.11-4.02 (m, 2H), 3.03 (s, 0.06H) 2.91-2.83 (m, 4H), 2.16-2.08 (m, 1H), 2.01-1.94 (m, 1H), 1.40 (t, J=7.6 Hz, 3H), 0.91 (t, J=7.4 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 202.5 (t, J=26.5 Hz), 135.3 (s), 134.7 (s), 126.8 (s), 126.3 (s), 120.7 (s), 119.9 (s), 116.1 (s), 108.9 (s), 74.9 (s), 60.7 (s), 51.0 (d, J=14.7 Hz), 31.2 (s), 24.1 (s), 22.4 (s), 13.9 (s), 7.8 (s); HRMS (ESI): m/z caled for C₁₇H₁₈D₃NO₂ [(M+H)⁺]: 275.1839, found: 275.1841.

2,3,5-Tri-O-benzyl-α,β-D-ribofuranose-1-d₁ (12u)

2,3,5-tri-O-benzyl-α,β-D-ribofuranose 11u (0.1 mmol), 5af (20 mol %), AcOK (0.1 mmol, 2 equiv) and CD₃COOD (0.4 mmol, 4 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 80° C. for 12 hours. 12u (iso1:iso2=1.7:1) was obtained as a yellow oil in 55% yield with 95% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 7.36-7.21 (m, 15H), 5.34 (t, J=9.7 Hz, 0.05H), 4.73-4.39 (m, 6H), 4.38-4.34 (m, 1H), 4.33-4.28 (m, 1H), 4.22 (dd, J=6.7, 4.7 Hz, 1H), 4.18 (s, 1H), 4.00-3.95 (m, 2H), 3.85 (d, J=4.6 Hz, 1H), 3.66 (dd, J=10.3, 2.7 Hz, 1H), 3.51-3.43 (m, 2H), 3.36 (s, 1H). ¹³C NMR (150 MHz, CDCl₃): iso1: δ 137.9 (s), 137.5 (s), 137.5 (s), 128.5 (s), 128.5 (s), 128.5 (s), 128.4 (s), 128.0 (s), 128.0 (s), 128.0 (s), 127.9 (s), 127.9 (s), 127.9 (s), 127.8 (s), 127.7 (s), 127.6 (s), 96.0 (t, J=26.4 Hz), 81.0 (s), 77.7 (s), 77.7 (s), 73.5 (s), 72.8 (s), 72.5 (s), 70.0 (s); iso2: δ 137.8 (s), 137.7 (s), 137.3 (s), 128.5 (s), 128.5 (s), 128.5 (s), 128.4 (s), 128.0 (s), 128.0 (s), 128.0 (s), 127.9 (s), 127.9 (s), 127.9 (s), 127.8 (s), 127.7 (s), 127.6 (s), 100.0 (t, J=25.8 Hz), 80.9 (s), 80.7 (s), 77.2 (s), 72.5 (s), 72.3 (s), 69.4 (s); HRMS (ESI): m/z caled for C₂₆H₂₇DNaO₅ [(M+Na)⁺]: 444.1897, found: 444.1898.

2,3,4,6-tetra-O-Benzyl-α,β-D-glucopyranose-1-d₁ (12v)

2,3,4,6-tetra-O-benzyl-α,β-D-glucopyranose 11v (0.1 mmol), 5af (40 mol %), AcOK (0.2 mmol, 2 equiv) and CD₃COOD (0.8 mmol, 8 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 120° C. for 12 hours. 12v was obtained as a white solid in 83% yield with 91% D-incorporation.

2,3,4,6-tetra-O-benzyl-α,β-D-glucopyranose-1-d₁ (91% D, 0.083 mmol), 5af (40 mol %) AcOK (0.17 mmol, 2 equiv) and CD₃COOD (0.67 mmol, 8 equiv) was dissolved in a mixture of D₂O (1 mL) and toluene (0.25 ml) in a reaction vessel (5 ml). Then the reaction mixture was vigorously stirred at 120° C. for 12 hours. 12v was obtained as a white solid in 77% yield (for two steps) with 99% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 7.35-7.11 (m, 20H), 5.22 (s, 0.01H), 4.97-4.40 (m, 9H), 4.07-3.96 (m, 2H), 3.71-3.50 (m, 4H), 3.43-3.21 (m, 2H); ¹³C NMR (150 MHz, CDCl₃) iso1: δ 138.5 (s), 138.4 (s), 138.0 (s), 137.70 (s), 128.5 (s), 128.4 (s), 128.4 (s), 128.4 (s), 128.1 (s), 128.0 (s), 128.0 (s), 127.9 (s), 127.9 (s), 127.9 (s), 127.7 (s), 127.7 (s), 127.7 (s), 127.6 (s), 97.1 (t, J=24.5 Hz), 84.6 (s), 83.0 (s), 77.8 (s), 75.7 (s), 75.0 (s), 74.70 (s), 74.60 (s), 73.5 (s), 73.2 (s), 68.9 (s); iso2: δ 138.8 (s), 138.2 (s), 137.9 (s), 137.8 (s), 128.5 (s), 128.4 (s), 128.4 (S), 128.4 (S), 128.1 (s), 128.0 (s), 128.0 (s), 127.9 (s), 127.9 (s), 127.8 (s), 127.7 (s), 127.7 (s), 127.7 (s), 127.6 (s), 91.9 (t, J=25.3 Hz), 81.7 (s), 79.9 (s), 77.7 (s), 75.7 (s), 75.0 (s), 73.5 (s), 73.2 (s), 70.2 (s), 68.6 (s); HRMS (ESI): m/z caled for C₃₄H₃₅DNaO₆ [(M+Na)⁺]: 564.2472, found: 564.2471.

Midecamycin-1,2-d₁,d₂ (12w)

Midecamycin (0.1 mmol), 5l (20 mol %) and AcOK (0.2 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 12w was obtained as a white solid in 80% yield with 90% D-incorporation.

Midecamycin (90% D, 0.08 mmol), 5l (20 mol %) and AcOK (0.16 mmol, 2 equiv) was dissolved in a mixture of D₂O (1 mL) and DCM (0.25 mL) in a reaction vessel (5 mL). Then the reaction mixture was vigorously stirred at 60° C. for 12 hours. 12w was obtained as a white solid in 62% yield (for two steps) with 99% D-incorporation at position 1 and uncertain D-incorporation at position 2. ¹H NMR (400 MHz, CDCl₃) δ 9.61 (s, 0.01H), 6.61 (dd, J=15.0, 10.7 Hz, 1H), 6.04 (dd, J=14.9, 10.6 Hz, 1H), 6.08-6.00 (m, 1H), 5.75 (t, J=13.0 Hz, 1H), 5.59 (dd, J=15.1, 9.4 Hz, 1H), 5.13-5.00 (m, 3H), 4.60 (d, J=10.0 Hz, 1H), 4.43 (d, J=7.1 Hz, 1H), 4.31 (s, 1H), 4.06 (dd, J=9.4, 3.8 Hz, 1H), 3.84 (d, J=9.2 Hz, 1H), 3.55-3.50 (m, 4H), 3.28-3.21 (m, 3H), 2.78-2.38 (m, 14-16H), 2.24 (d, J=13.0 Hz, 1H), 2.12 (dd, J=24.6, 11.5 Hz, 2H), 2.00 (d, J=14.3 Hz, 1H), 1.84 (dd, J=15.9, 12.0 Hz, 2H), 1.49-1.34 (m, 2H), 1.28-1.06 (m, 17H), 1.02-0.84 (m, 4H); ¹³C NMR (150 MHz, CDCl₃) δ 202.5-200.1 (m), 174.4 (s), 173.9 (s), 169.9 (s), 135.8 (s), 132.9 (s), 131.9 (s), 127.5 (s), 103.6 (s), 96.9 (s), 84.8 (s), 77.6 (s), 75.9 (s), 73.2 (s), 72.9 (s), 71.6 (s), 69.4 (s), 69.0 (s), 68.7 (s), 63.5 (s), 62.5 (s), 42.2 (s), 41.9 (s), 41.6 (s), 41.0 (s), 37.1 (s), 33.5 (s), 30.4 (s), 28.7 (s), 27.6 (s), 27.6 (s), 25.4 (s), 20.4 (s), 18.8 (s), 17.7 (s), 14.7 (s), 9.3 (s), 8.9 (s); HRMS (ESI): m/z caled for C₄₁H₆₅D₃NO₁₅ [(M+H)⁺]: 817.4777, found: 817.4795.

Example 4 Preparation of Catalysts 5ah and 5p

Following the modified procedure of reported literature, a flame-dried round bottom flask was charged with 6-bromo-4,4a,9,9a-tetrahydroindeno[2,1-b][1,4]oxazin-3(2H)-one (1.0 g, 3.73 mmol) and CH₂Cl₂ (18 mL). Trimethyloxonium tetrafluoroborate (549 mg, 3.73 mmol) was added, and the reaction mixture stirred for 12 hours at 23° C. 3,5-Bis(trifluoromethyl)phenylhydrazine (904 mg, 3.73 mmol) was then added and allowed to stir for 12 hours at ambient temperature. The solvent was evaporated and chlorobenzene (34 mL) was added, followed by triethyl orthoformate (1.55 ml, 9.26 mmol). The flask was equipped with a reflux condenser and heated to 110° C. and stirred at this temperature for 12 hours. At this time, additional triethylorthoformate (1.55 mL, 9.26 mmol) was added and stirring at 110° C. was continued for additional 12 hours. Upon cooling, concentrated in vacuo. The product was purified by flash column chromatography to get the title compound 5ah as a tan solid (55% yield). ¹H NMR (400 MHz, CDCl₃) δ 13.30 (s, 1H), 8.85 (s, 2H), 8.21 (s, 1H), 7.92 (s, 1H), 7.35-7.29 (m, 1H), 7.08 (d, J=8.1 Hz, 1H), 6.56 (d, J=3.9 Hz, 1H), 5.10 (s, 2H), 5.02 (t, J=4.4 Hz, 1H), 3.27 (dd, J=17.3, 4.7 Hz, 1H), 3.11 (d, J=17.3 Hz, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 150.1 (s), 144.6-142.7 (m), 139.1 (s), 137.2 (s), 136.3 (s), 133.7 (q, J=34.8 Hz), 130.2 (d, J=493.9 Hz), 126.8 (s), 124.0 (dd, J=7.9, 4.2 Hz), 123.6 (s), 121.4 (d, J=3.2 Hz), 121.2 (s), 120.9 (s), 77.7 (s), 62.2 (s), 60.4 (s), 37.2 (s); HRMS (EI): m/z caled for C₂₀H₁₂BrF₆N₃O [(M−H)⁺]: 503.0068, found: 503.0063.

Following the modified procedure of reported literature, a flame-dried round bottom flask was charged with 6-nitro-4,4a,9,9a-tetrahydroindeno[2,1-b][1,4]oxazin-3(2H)-one (1.0 g, 4.27 mmol) and CH₂Cl₂ (21 mL). Trimethyloxonium tetrafluoroborate (769 mg, 4.27 mmol) was added, and the reaction mixture stirred for 12 hours at 23° C. 3,5-bis(trifluoromethyl)phenylhydrazine (1,042 mg, 4.27 mmol) was then added and allowed to stir for 12 hours at ambient temperature. The solvent was evaporated and chlorobenzene (41 mL) was added, followed by triethyl orthoformate (1.78 mL, 10.69 mmol). The flask was equipped with a reflux condenser and heated to 110° C. and stirred at this temperature for 12 hours. At this time, additional triethylorthoformate (1.78 mL, 10.69 mmol) was added and stirring at 110° C. was continued for 12 more hours. Upon cooling, concentrated in vacuo. The product was purified by flash column chromatography to get the title compound 5p as a tan solid (31% yield). ¹H NMR (400 MHz, DMSO-d₆) δ 11.85 (s, 1H), 8.70 (s, 2H), 8.59 (d, J=9.9 Hz, 2H), 8.32 (dd, J=8.3, 1.8 Hz, 1H), 7.74 (d, J=8.4 Hz, 1H), 6.25 (d, J=3.9 Hz, 1H), 5.39 (d, J=16.5 Hz, 1H), 5.17 (d, J=16.5 Hz, 1H), 5.05 (t, J=4.3 Hz, 1H), 3.60 (dd, J=17.8, 4.6 Hz, 1H), 3.32 (d, J=17.9 Hz, 1H); ¹³C NMR (100 MHz, DMSO-d₆) δ 149.7 (s), 149.0 (s), 147.2 (s), 143.7 (s), 137.4 (s), 136.4 (s), 132.0 (d, J=34.2 Hz), 125.9 (d, J=171.6 Hz), 124.5 (m), 123.9 (s), 122.2 (m), 121.2 (s), 120.3 (s), 77.2 (s), 60.8 (s), 59.7 (s), 37.1 (s); HRMS (EI): m/z caled for C₂₀H₁₂F₆N₄O₃ [(M−H)⁺]: 470.0814, found: 470.0815.

Example 5 Preparation of Substrates

Following the modified procedure of reported literature, 1,4-phthalaldehyde (470 mg, 3.5 mmol), ethylacetoacetate (910 mg, 7 mmol), and ammonium hydroxide solution (364 μL, 2.6 mmol) in ethanol (2 mL) was stirred at reflux for 6 h. After completion of the reaction, as indicated by TLC, the reaction mixture was concentrated in vacuo. The crude product was purified by flash column chromatography (EtOAc/petroleum ether=1/4). The title compound 6be was obtained as a yellow solid (378 mg, 41%). ¹H NMR (400 MHz, CDCl₃) δ 9.92 (s, 1H), 7.73 (d, J=8.2 Hz, 2H), 7.45 (d, J=8.2 Hz, 2H), 6.07 (s, 1H), 5.05 (s, 1H), 4.11-4.03 (m, 4H), 2.33 (s, 6H), 1.20 (t, J=7.1 Hz, 6H).

Following the modified procedure reported in literature, in a flask were introduced O-desmethylvenlafaxine (670 mg, 2.55 mmol), DMF (3 mL), potassium carbonate (690 mg, 5 mmol) and 4-fluorobenzaldehyde (310 mg, 2.5 mmol). The resulting mixture was stirred at 120° C. overnight. The reaction mixture was diluted with water (30 mL) and the product was extracted with EtOAc (3×30 mL). The combined organic layers were washed sequentially with 0.5 M aqueous NaOH solution (30 mL) and saturated aqueous NaHCO₃ solution (2×30 mL), and dried over anhydrous MgSO₄. The organic layer was filtered and concentrated under reduced pressure. The crude residue was purified by silica gel chromatography using MeOH/DCM (1/50-1/10) as eluent to give the product 6bf as a yellow oil (693 mg, 73%). ¹H NMR (400 MHz, CDCl₃) δ 9.83 (s, 1H), 7.76 (d, J=8.2 Hz, 2H), 7.11 (d, J=8.5 Hz, 2H), 6.98 (d, J=8.5 Hz, 2H), 6.92 (d, J=8.3 Hz, 2H), 3.24 (t, J=12.5 Hz, 1H), 2.96 (dd, J=12.3, 3.1 Hz, 1H), 2.33-2.23 (m, 7H), 1.73-1.64 (m, 3H), 1.48 (t, J=15.9 Hz, 3H), 1.33-1.21 (m, 2H), 0.95-0.80 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 190.6 (s), 163.1 (s), 153.7 (s), 137.4 (s), 131.9 (s), 131.2 (s), 130.8 (s), 119.7 (s), 117.5 (s), 74.1 (s), 61.0 (s), 51.9 (s), 45.5 (s), 38.1 (s), 31.2 (s), 26.0 (s), 21.6 (s), 21.3 (s).

Following the modified procedure reported in literature, hydroxyzine hydrochloride (1.12 g, 2.5 mmol) was diluted with toluene (10 mL), then 2-fluorobenzaldehyde (340 mg, 2.75 mmol), tetrabutylammonium bromide (TBAB) (200 mg, 0.66 mmol) and a solution of potassium hydroxide (560 mg, 10 mmol) in water (570 μL) were added. The reaction mixture was vigorously stirred at 90° C. under nitrogen overnight. When the reaction was completed, the solution was concentrated in vacuo. The crude residue was purified by silica gel chromatography to give product 6bg (677 mg, 57% yield). ¹H NMR (400 MHz, CDCl₃) δ 10.49 (d, J=0.5 Hz, 1H), 7.81 (dd, J=7.7, 1.8 Hz, 1H), 7.54-7.50 (m, 1H), 7.37-7.32 (m, 4H), 7.30-7.15 (m, 5H), 7.02 (t, J=7.5 Hz, 1H), 6.97 (d, J=8.4 Hz, 1H), 4.22 (dd, J=7.9, 2.8 Hz, 3H), 3.88-3.84 (m, 2H), 3.73 (t, J=5.5 Hz, 2H), 2.70-2.42 (m, 10H); ¹³C NMR (100 MHz, CDCl₃) δ 189.8 (s), 161.2 (s), 142.0 (s), 141.2 (s), 135.9 (s), 132.6 (s), 129.2 (s), 128.7 (s), 128.6 (s), 128.4 (s), 127.8 (s), 127.2 (s), 125.1 (s), 121.0 (s), 112.8 (s), 75.3 (s), 69.3 (s), 68.9 (s), 68.1 (s), 57.6 (s), 53.8 (s), 51.3 (s).

(2′-(2H-Tetrazol-5-yl)biphenyl-4-yl)methyl)-2-butyl-4-chloro-1H-imidazole-5-carbaldehyde (6bi): Losartan (1.7 g, 4 mmol) and IBX (2-iodoxybenzoic acid, 1.345 g, 4.8 mmol) were added in DMSO (20 mL) and stirred at room temperature for 6 h. CH₂Cl₂ (120 mL) was added and the solution was washed with water (3×120 mL), saturated NaHCO₃ solution (3×120 mL), and brine (1×120 mL). The solvent was removed after drying (Na₂SO₄) in vacuo to yield the product 6bi (888 mg, 53%). ¹H NMR (400 MHz, CDCl₃) δ 9.63 (s, 1H), 7.90 (dd, J=7.7, 1.1 Hz, 1H), 7.62-7.54 (m, 1H), 7.54-7.46 (m, 1H), 7.39 (d, J=7.6 Hz, 1H), 7.08 (d, J=7.9 Hz, 2H), 6.95 (d, J=7.8 Hz, 2H), 5.49 (s, 2H), 2.79-2.48 (m, 2H), 1.67-1.65 (m, 2H), 1.41-1.21 (m, 2H), 0.85 (t, J=7.3 Hz, 3H).

Step 1: Following the modified procedure reported in literature, to a stirred solution of indometacin (1.0 g, 2.86 mmol) in THF (15 mL) was added a 1M solution of borane tetrahydrofuran complex (3 mL, 3.0 mmol) at 0° C. The mixture was allowed to warm up to room temperature and stirred for 18 h. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography (DCM/MeOH=50/1) to give its-a (734 mg, 74%) as a yellow solid.

Step 2: Following the modified procedure reported in literature, to a stirred solution of its-a (734 mg, 2.15 mmol) in EtOAc (7.34 mL) was added IBX (1.5 g, 5.3 mmol) at room temperature and the resulting mixture was heated at 80° C. for 2 h. The mixture was filtered and filtrate was concentrated under reduced pressure to give 11s (490 mg, 66%) as a powder. ¹H NMR (400 MHz, CDCl₃) δ 9.71 (t, J=2.1 Hz, 1H), 7.67 (d, J=8.4 Hz, 2H), 7.48 (d, J=8.4 Hz, 2H), 6.87-6.84 (m, 2H), 6.69 (dd, J=9.0, 2.4 Hz, 1H), 3.82 (s, 3H), 3.72 (d, J=2.0 Hz, 2H), 2.38 (s, 3H).

Step 1: Following the modified procedure reported in literature, to a stirred solution of Etodolac (2.0 g, 6.97 mmol) in dry THE (15.5 mL) under nitrogen was added a solution of LiAlH₄ (800 mg, 21 mmol) in dry THF (10.5 mL) dropwise and the resulting mixture was warmed to room temperature and stirred overnight. The reaction was slowly quenched with EtOAc (30 mL) and poured into water. The resulting emulsion was filtered and the filtrate was extracted with EtOAc. The combined organic layers were washed with brine and dried over anhydrous MgSO₄. The organic layer was filtered and concentrated under reduced pressure. The crude residue was purified by silica gel chromatography to give 11t-a (1.14 g, 59%) as a yellow oil.

Step 2: Following the modified procedure reported in literature, to a stirred solution of 11t-a (1.14 g, 4.17 mmol) in CH₃CN (5.38 mL), DMSO (5.38 mL) and Et₃N (5.38 mL) was added pyridine sulfur trioxide (3.96 g, 24.8 mmol) and the resulting mixture was stirred at room temperature for 40 min. The mixture was poured into water and extracted with EtOAc. The combined organic layers were washed sequentially with 3% aquenes HCl solution, saturated aqueous NaHCO₃ solution and brine, and dried over anhydrous MgSO₄. The organic layer was filtered and concentrated under reduced pressure. The crude residue was purified by silica gel chromatography to give product lit (720 mg, 63%). ¹H NMR (400 MHz, CDCl₃) δ 9.76 (t, J=1.6 Hz, 1H), 8.41 (s, 1H), 7.37 (d, J=7.7 Hz, 1H), 7.09 (t, J=7.5 Hz, 1H), 7.03 (dd, J=6.7, 0.5 Hz, 1H), 4.08-3.97 (m, 2H), 3.06 (d, J=1.6 Hz, 2H), 2.91-2.78 (m, 4H), 2.16-2.08 (m, 1H), 1.96 (dd, J=14.5, 7.3 Hz, 1H), 1.37 (t, J=7.6 Hz, 3H), 0.87 (t, J=7.4 Hz, 3H).

Example 6. Recovery of Hydrogen from Deuterium at α-Position of Aldehyde (FIG. 4C)

Compound 12l (0.5 mmol, 68 mg, D¹=98%; D²=97%) and organocatalyst 13 (16.3 mg, 10 mol %) was dissolved in a mixture H₂O (1 mL) and DCM (0.25 ml). Then the reaction was vigorously stirred at 30° C. for 12 hours. After purification, compound 14 was obtained as a colorless oil in 81% yield with 98% D-incorporation. ¹H NMR (400 MHz, CDCl₃) δ 9.69 (d, J=1.4 Hz, 0.02H), 7.41-7.37 (m, 2H), 7.35-7.28 (m, 1H), 7.24-7.21 (m, 2H), 3.64 (q, J=7.1 Hz, 1H), 1.45 (d, J=7.1 Hz, 3H); ¹³C NMR (150 MHz, CDCl₃) δ 200.8 (t, J=26.6 Hz), 137.7 (s), 129.1 (s), 128.3 (s), 127.5 (s), 52.8 (t, J=4.1 Hz), 14.6 (s).

Example 7. Gram Scale Synthesis, Recycling and Reuse of D₂O and Synthetic Applications

A gram-scale HDE reaction was conducted using aldehyde 6c and the same reaction conditions employed in the small-scale process (FIG. 3B). In contrast to the small-scale process, the gram-scale counterpart formed 7c in a similar yield and with a comparable level of D-incorporation (FIG. 5A). Furthermore, the recovered D₂O containing solvent can be used in a second and third reaction without causing a decrease in yield and D-incorporation level.

As stated above, aldehydes are versatile starting materials and intermediates in organic synthesis. Further experiments demonstrated that 1-D-aldehydes formed in the present HDE process may be utilized in transformations that produce the deuterated analogs of important substances including aryl methanols and pharmaceuticals (FIG. 5B). For example, Cannizzaro reactions of 1-D-aldehydes conducted in concentrated KOH were found to produce the corresponding dideuterated benzyl alcohols in high yields. Furthermore, several deuterated analogs of clinically important drugs were synthesized using appropriate deuterated aldehydes as starting materials (FIG. 5C).

A. Gram-Scale Synthesis of Deuterated Aldehyde and Recycling and Subsequent Use of Recoved D2O (FIG. 5A)

Cycle 1: A mixture of 4-Bromobenzaldehyde 6b (30 mmol, 5.55 g), 5o (10 mol %, 1.41 g) and NaHCO₃ (30 mmol, 2.52 g) in D₂O (60 mL) and toluene (15 mL) was vigorously stirred at 40° C. for 12 hours. After cooling to room temperature, the reaction mixture was extracted with DCM for three time. The organic layers were combined and dried over anhydrous sodium sulfate, concentrated in vacuo, and purified by column chromatography. Deuterated aldehyde 7b was obtained as a yellow solid in 86% yield with 98% D-incorporation.

Cycle 2: 4-Bromobenzaldehyde 6b (30 mmol, 5.55 g) and 5o (10 mol %, 1.41 g) were added to D₂O (separated from Cycle 1) and toluene (15 mL). The reaction was vigorously stirred at 40° C. for 12 hours. After cooling to room temperature, the reaction was extracted with DCM for three time. The organic layers were combined and dried over anhydrous sodium sulfate, concentrated in vacuo, and purified by column chromatography. Deuterated aldehyde 7b was obtained as a yellow solid in 90% yield with 98% D-incorporation.

Cycle 3: The same operation was carried out as Cycle 2. Deuterated aldehyde 7b was obtained as a yellow solid in 91% yield with 95% D-incorporation.

B. Preparation of Deuterated Benzyl Alcohols Through Cannizzaro Reaction (FIG. 5B)

General procedure: According to the literature method, the aromatic aldehyde (1.0 mmol) was added to a saturated solution of potassium hydroxide (4.0 mmol), and the mixture was stirred at room temperature for 1-2 hours. The thick slurry was diluted with water (10 mL), and the resulting mixture was extracted with CH₂Cl₂ (20 mL). The extracts were washed with water and dried over MgSO₄, and the solvent was removed under reduced pressure to obtain the crude benzyl alcohol product. The crude products were purified by chromatography to obtain the pure product.

4-Methoxybenzenemethan-d₂-ol (15a): ¹H NMR (400 MHz, CDCl₃) δ 7.25 (dt, J=8.8, 2.8 Hz, 2H), 6.87 (dt, J=8.8, 2.8 Hz, 2H), 4.54 (s, 0.03H), 3.78 (s, 3H), 2.19 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 159.2 (s), 133.1 (s), 128.7 (s), 113.9 (s), 64.2 (quint, J=21.7 Hz), 55.3 (s).

4-Bromobenzenemethan-d₂-ol (15b): ¹H NMR (400 MHz, CDCl₃) δ 7.45 (d, J=8.3 Hz, 2H), 7.19 (d, J=8.4 Hz, 2H), 4.56 (s, 0.04H), 2.44 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 139.6 (s), 131.6 (s), 128.7 (s), 121.5 (s), 63.8 (quint, J=21.8 Hz).

Benzenemethan-d₂-ol (15e): ¹H NMR (400 MHz, CDCl₃) δ 7.41-7.27 (m, 5H), 4.64-4.62 (m, 0.03H), 2.27 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 140.8 (s), 128.6 (s), 127.7 (s), 127.1 (s), 64.6 (quint, J=21.8 Hz).

3-Nitrobenzenemethan-d₂-ol (15X): ¹H NMR (400 MHz, CDCl₃) δ 8.20 (s, 1H), 8.10 (d, J=8.2 Hz, 1H), 7.67 (d, J=7.6 Hz, 1H), 7.50 (t, J=7.9 Hz, 1H), 4.77 (s, 0.03H), 2.56 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 148.3 (s), 142.8 (s), 132.8 (s), 129.5 (s), 122.5 (s), 121.5 (s), 63.7-62.7 (m).

1-Naphthalenemethan-α,α-d₂-ol (15an): ¹H NMR (400 MHz, CDCl₃) δ 8.10-8.06 (m, 1H), 7.89 (dd, J=5.9, 3.6 Hz, 1H), 7.82 (d, J=7.8 Hz, 1H), 7.57-7.50 (m, 2H), 7.49-7.41 (m, 2H), 5.03 (s, 0.04H), 2.41 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 136.2 (s), 133.8 (s), 131.8 (s), 128.7 (s), 128.6 (s), 126.4 (s), 125.9 (s), 125.5 (s), 125.4 (s), 123.7 (s), 62.8 (quint, J=21.9 Hz).

1-Thiophenemethan-d₂-ol (15aq): ¹H NMR (400 MHz, CDCl₃) δ 7.31 (dd, J=5.0, 3.0 Hz, 1H), 7.22 (dd, J=2.9, 1.2 Hz, 1H), 7.09 (dd, J=5.0, 1.2 Hz, 1H), 4.65 (s, 0.03H), 2.03 (s, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 142.1 (s), 126.8 (s), 126.3 (s), 122.1 (s), 60.5-59.5 (m).

C. Preparation of Deuterated Pharmaceutical Compounds (FIG. 5C)

Procedure for the Synthesis of Nitrendipine

According to literature method, a solution of the deuterated 3-nitrobenzaldehyde 7w (76 mg, 0.5 mmol, 99% D), 3-amino-2-butanoate (0.5 mmol) and ethyl acetoacetate (0.5 mmol) in EtOH (1 mL) was stirred at reflux for 6 hours. After completion of the reaction, as indicated by TLC, the reaction mixture was cooled to room temperature and concentrated in vacuo. The crude product was purified by flash column chromatography (EtOAc/petroleum ether=1:4). The title compound was obtained as a yellow solid (144 mg, 78%), D-incorporation: 99%. ¹H NMR (400 MHz, CDCl₃) δ 8.10 (t, J=1.9 Hz, 1H), 8.01-7.97 (m, 1H), 7.65-7.60 (m, 1H), 7.36 (t, J=7.9 Hz, 1H), 6.10 (s, 1H), 5.08 (s, 0.01H), 4.12-4.04 (m, 2H), 3.63 (s, 3H), 2.35 (d, J=2.3 Hz, 6H), 1.22 (t, J=7.1 Hz, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 167.7 (s), 167.2 (s), 149.8 (s), 148.2 (s), 145.2 (s), 145.0 (s), 134.4 (s), 128.7 (s), 122.9 (s), 121.4 (s), 103.2 (s), 102.9 (s), 60.1 (s), 51.2 (s), 39.5 (t, J 19.2 Hz), 19.6 (s), 19.5 (s), 14.3 (s); HRMS (ESI): m/z caled for C₁₈H₂₀DN₂O₆[(M+H)⁺]: 362.1462, found: 362.1461.

Procedure for the Synthesis of Salbutamol

Step 1: According to the literature method, a solution of trimethylsulfonium bromide (518 mg, 1.1 equiv) and KOH powder (219 mg, 1.3 equiv) in CH₃CN (3 mL) was stirred at 50° C. for 10 min. Then aldehyde 7al (579 mg, 3 mmol, 98% D) were added and stirred at 60° C. for another three hours. The reaction mixture then was cooled to room temperature, filtered and concentrated in vacuo. The crude product 16 was used without purification in the next step.

Step 2: According to the literature method, compound 16 (400 mg) was dissolved in tert-butylamine (2 mL) and stirred at 110° C. for 15 hours. The reaction mixture was cooled to room temperature, concentrated in vacuo and added solvent (EtOAc/petroleum ether=1/2). Then the reaction was refluxed until became clear, cooled to 30° C. for 1 h, then cooled to 4° C. overnight, filtered and dried, 17 was obtained in 75% yield for two steps.

Step 3: According to the literature method, compound 17 (60 mg) in 50% EtOH (0.8 mL) was added concentrated hydrochloric acid until the pH was adjusted to 5. The reaction mixture was stirred at 25° C. for 50 hours. NaOH (10%) was added until pH value was about 9-10. The reaction mixture was concentrated in vacuo, and the product was separated by preparative TLC. Salbutamol was obtained in 95% yield with 98% D-incorporation.)¹H NMR (400 MHz, DMSO-d₆) δ 7.32 (d, J=2.2 Hz, 1H), 7.06 (dd, J=8.2, 2.2 Hz, 1H), 6.79 (d, J=8.2 Hz, 1H), 4.46 (s, 2H), 4.28 (s, 0.02H), 2.84 (dd, J=26.4, 12.2 Hz, 2H), 1.27 (s, 9H); ¹³C NMR (100 MHz, DMSO-d₆) δ 153.7 (s), 131.9 (s), 128.3 (s), 125.0 (s), 124.9 (s), 114.2 (s), 68.5 (m), 58.1 (s), 55.5 (s), 48.6 (s), 25.3 (s); HRMS (ESI): m/z caled for C₁₃H₂₀DNO₃ [(M+H)⁺]: 241.1662, found: 241.1663.

Procedure for the Synthesis of Cloperastine

Step 1: According to the literature method, a solution of deuterated 4-chlorobenzaldehyde 7l (140 mg, 1 mmol, 98% D) in dry THF (4 mL) was added dropwise phenyl magnesium bromide solution (1 M, 1.3 mL, 1.3 equiv) at 0° C. After the addition was complete, the mixture was allowed to stir at room temperature for 4 hours. The reaction was quenched with 1 M HCl and extracted with EtOAc. The organic layer was washed with water followed by brine. The organic layer was dried with MgSO₄ and concentrated. The product was purified by flash chromatography with EtOAc/petroleum ether=1:4, and 18 was obtained in 95% yield.

Step 2: According to the literature method, to a solution of 18 (0.4 mmol) in CH₂Cl₂ (4 mL) was added 1-(2-chloroethyl) piperidine hydrochloride (120 mg, 0.6 mmol). The resulting solution was cooled at 0° C. followed by the addition of NaOH (48 mg, 1.2 mmol). After the mixture had been stirred for 20 min at 0° C. and then overnight at room temperature, it was quenched with H₂O and extracted with CH₂Cl₂. The organic layer was washed with brine, dried over anhydrous Na₂SO₄, and concentrated under reduced pressure. The residue was purified by silica gel chromatography to get cloperastine (98 mg, 75% yield, 98% D-incorporation). ¹H NMR (400 MHz, CDCl₃) δ 7.27-7.16 (m, 9H), 5.29 (s, 0.02H), 3.60 (t, J=5.9 Hz, 2H), 2.69 (t, J=5.9 Hz, 2H), 2.53 (s, 4H), 1.63-1.57 (m, 4H), 1.39 (d, J=4.8 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 141.4 (s), 140.6 (s), 132.7 (s), 128.1 (s), 128.1 (s), 128.0 (s), 127.3 (s), 126.6 (s), 82.9-82.7 (m), 66.7 (s), 58.2 (s), 54.7 (s), 25.6 (s), 23.9 (s); HRMS (ESI): m/z caled for C₂₀H₂₄DClNO [(M+H)⁺]: 331.1687, Found: 331.1690.

Procedure for the Synthesis of Tadalafil

Step 1: According to the literature method, D-tryptophan methyl ester hydrochloride 19 (400 mg, 1.57 mmol) was suspended in CH₃CN (4 mL) and added deuterated piperonal 7ah (284 mg, 1.87 mmol, 98% D) at room temperature. The mixture was stirred at 80° C. for 15 hours. The reaction mixture then was cooled to ambient temperature, filtered, and the solid washed with cold CH₃CN. The product was dried under vacuum at less than 60° C. to obtain compound 20 (308 mg, 80% yield).

Step 2: According to the literature method, compound 20 (270 mg, 0.7 mmol) were suspended in DCM (2.5 mL). The mixture was cooled to 0-5° C., and triethylamine (194 mg, 1.82 mmol) were added. Subsequently, chloroacetyl chloride (108 mg, 0.95 mmol) in DCM (0.42 mL) were added dropwise, keeping the temperature under 10° C. Then the reaction was stirred at 0-10° C. for 10 min. After completion of the reaction as monitored by TLC, water (0.4 mL) were added to quench the reaction. The mixture was stirred for 2 min and organic layer was separated, concentrated in vacuo. The resulting solid was washed with methanol to give the title compound 21 as a pale yellow solid (341 mg, 80% yield).

Step 3: According to the literature method, a solution of 21 (214 mg, 0.5 mmol) and 25-30% CH₃NH₂ (a solution in water, 155.3 mg, 1.25 mmol, 2.5 equiv) in EtOH (1.5 mL) was heated to reflux for 45 min. The reaction mixture was cooled to room temperature, filtered, and the resulting solid was washed with water and methanol and dried to give deuterated tadalafil as a pale white solid (284 mg, 73% yield, 98% D-incorporation). ¹H NMR (400 MHz, DMSO-d₆) δ 11.05 (s, 1H), 7.55 (d, J=7.7 Hz, 1H), 7.31 (d, J=8.0 Hz, 1H), 7.06 (t, J=7.0 Hz, 1H), 7.00 (t, J=7.1 Hz, 1H), 6.88 (s, 1H), 6.79 (s, 2H), 6.14 (s, 0.02H), 5.93 (s, 2H), 4.40 (dd, J=11.5, 4.1 Hz, 1H), 4.22-4.10 (m, 1H), 3.95 (d, J=17.2 Hz, 1H), 3.53 (dd, J=15.8, 4.5 Hz, 1H), 3.08-2.82 (m, 4H); ¹³C NMR (100 MHz, DMSO-d₆) δ 166.9 (s), 166.6 (s), 147.0 (s), 146.1 (s), 136.9 (s), 136.2 (s), 133.9 (s), 125.7 (s), 121.2 (s), 119.3 (s), 118.8 (s), 118.1 (s), 111.3 (s), 108.1 (s), 106.9 (s), 104.7 (s), 100.9 (s), 55.5 (s), 54.96 (m), 51.4 (s), 32.8 (s), 23.1 (s). HRMS (ESI): m/z caled for C₂₂H₁₉DN₃O₄ [(M+H)⁺]: 391.1517, found: 391.1521.

Procedure for the Synthesis of Diltiazem Hydrochloride

Step 1: According to the literature method, sodium (126 mg, 5.48 mmol) was dissolved in methanol (1.32 mL), then p-anisaldehyde 7a (450 mg, 3.31 mol, 98% D) and methyl chloroacetate (534 mg, 4.92 mmol) was added over 4.5 hours at 0° C. and stirring was continued for further 4 hours. The reaction mixture was poured into a solution of AcOH (60 mg) in water (7.5 mL) over 20 min at 0° C. The reaction was stirred for 1 h, then the crystals were collected by filtration and washed with cold water and cold MeOH to give a crude product, which was recrystallized from hot MeOH to give 22 (922 mg, 67% yield).

Step 2: According to the literature method, a solution of 22 (520 mg, 2.5 mmol) and 28% aqueous FeCl₃.6H₂O (1 drop) in chlorobenzene (2.64 mL) was heated to 80-85° C. 2-Aminothiophenol (328.6 mg, 2.62 mmol) was added over 30 min, and the resulting mixture was stirred at 115° C. for 45 min. H₂O (1 drop) in MeOH (90 μL) were added and stirred at reflux for 30 min. Methanesulfonic acid (9.6 mg, 0.1 mmol) was then added and the reflux was maintained for an additional 18 hours. After cooling to room temperature, the solvent was concentrated under reduced pressure to give the crude benzothiazepinone 23 as a yellow powder. The residue was purified by column chromatography (cyclohexane:EtOAc=8:2, v/v) to afford 20 mg white powder (yield: 69%).

Step 3: According to the literature method, to a solution of benzothiazepinone 23 (414 mg, 1.41 mmol) in EtOAc (3.5 mL) was added 2-(dimethylamino) ethyl chloride hydrochloride (224 mg, 1.56 mmol). Under vigorous stirring were then added potassium carbonate (419 mg, 3.03 mmol) and H₂O (64 mg). The resulting mixture was heated at reflux for 12 h. After cooling, the mixture was filtered to remove salts, and the filtrate was concentrated under reduced pressure to give the crude benzothiazepinone 24. The residue was purified by column chromatography (CH₂Cl₂:MeOH=98:2) to afford 366 mg of yellow oil (yield: 70%).

Step 4: According to the literature method, a solution of 24 (0.317 mmol), Ac₂O (1 mmol), Et₃N (2 mmol) and DMAP (0.03 mmol) in CH₂Cl₂ (5 mL) was heated at reflux under N₂ for 5 hours. The solution was poured into a mixture of ice and brine. The organic layer was separated and the aqueous layer was extracted with CH₂Cl₂ (10 mL). The combined organic layers were washed with 5% NH₄OH (5 mL) solution, dried over Na₂SO₄ and evaporated. The residue was dissolved in MeOH (2 mL) and treated with a HCl solution in dioxane till pH was around 2. Ether (3 mL) was added to the resulting solution. The precipitate was collected by filtration and washed with 10% MeOH-ether to afford diltiazem hydrochloride (128 mg, 90% yield, 98% D). ¹H NMR (400 MHz, CD₃OD) δ 7.82-7.79 (m, 1H), 7.65 (dd, J=5.5, 1.9 Hz, 2H), 7.46-7.39 (m, 3H), 6.91 (d, J=8.8 Hz, 2H), 5.12 (s, 0.01H), 5.09 (s, 1H), 4.53-4.44 (m, 1H), 4.27-4.18 (m, 1H), 3.81 (s, 3H), 3.69-3.61 (m, 1H), 3.43-3.31 (m, 1H), 2.98 (d, J=24.6 Hz, 6H), 1.87 (s, 3H); ¹³C NMR (100 MHz, CD₃OD) δ 170.1 (s), 169.1 (s), 160.1 (s), 144.4 (s), 135.5 (s), 131.5 (s), 130.6 (s), 129.2 (s), 128.4 (s), 128.2 (s), 126.3 (s), 113.3 (s), 71.1 (s), 54.5 (s), 54.4 (s), 44.6 (s), 42.6 (s), 18.8 (s); HRMS (ESI): m/z caled for C₂₂H₂₆DN₂O₄S [(M+H)⁺]: 416.1754, found: 416.1759.

In summary, the studies above demonstrates an NHC promoted reversible hydrogen-deuterium exchange (HDE) reaction for the efficient synthesis of synthetically valued C-1 deuterated aldehydes. A new reactivity of NHC catalysis was successfully implemented to overcome the overwhelmingly kinetically favorable, irreversible benzoin condensation reaction and achieved the desired thermodynamic reversibility to drive the formation of desired deuterated products. The unrivaled capacities of the NHC catalysed reversible processes was demonstrated by directly converting aldehydes to C-1 deuterated counterparts using D2O as the deuterium source under mild reaction conditions without requiring additional functionality manipulation and thus with minimal byproduct formation. Furthermore, this operationally simple and cost-effective protocol serves as a general and truly practical approach to a wide variety of 1-D-aldehydes including aryl, alkyl and alkenyl aldehydes, which may be difficult to access by existing methods (a representative cost calculation is shown in Table 5). In addition, the process described herein enables chemoselective late-stage deuterium incorporation into complex, native therapeutic agents and natural products (total 104 examples) with uniformly high levels (>95%) of deuterium incorporation. Thus the process disclosed herein may enable facile access to a wide range of synthetically versatile compounds and accelerate the construction of new deuterated compounds for drug discovery.

TABLE 5
Cost Calculation for the Preparation of Deuterated Benzaldehyde
				Quantity for	Price for
				producing 1 g	producing 1
Compound	Vendor	Cost/g	MW	product 7d	g product 7d
	Sigma-Aldrich	$29.80/100 g	106	0.01335 mol × 106 = 1.42 g	$0.298/g × 1.42 g = $0.42
	Self preparation	$40/g	427.1	0.01335 × 10 mol % × 427.1 = 0.57 g	$40/g × 0.57 g = $22.8
D2O	Sigma-Aldrich	$1,160/1 kg	20	1000 × 1.1/(107 ×	$1.16/g × 14.7 =
				70%) = 14.7 g	$17.05
K2CO3	Fisher	$24.66/500 g	138	0.01335 × 138 =	$0.049/g ×
				1.84 g	1.84 = $0.09
Toluene	Sigma-Aldrich	$45/2 L	92	3.3 mL	0.0225/mL ×
(anhydrous)					3.3 = $0.074
	Sigma-Aldrich	$570/g	107
	Method herein	$40.43/ga	107

It is understood that the foregoing detailed description and accompanying examples are merely illustrative and are not to be taken as limitations upon the scope of the invention, which is defined solely by the appended claims and their equivalents.

Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications, including without limitation those relating to the chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, or methods of use of the invention, may be made without departing from the spirit and scope thereof.

For reasons of completeness, various aspects of the invention are set out in the following numbered clauses:

Clause 1. A method for preparing a deuterated aldehyde of formula

R^Z—C(O)—D

wherein

R^Z is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^a, and R^Z is optionally deuterated;

R^a at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted;

the method comprising:

contacting an aldehyde of formula

R^Z′—C(O)—H

with an N-heterocyclic carbene catalyst in a solvent comprising D₂O, thereby producing the deuterated aldehyde,

wherein R^Z′ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more R^b;

R^b at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted.

Clause 2. The method of clause 1, wherein R^Z is an optionally substituted aryl or an optionally substituted heteroaryl.

Clause 3. The method of clause 1, wherein R^Z is an optionally substituted alkenyl or an optionally substituted cycloalkenyl.

Clause 4. The method of clause 1, wherein R^Z is an optionally substituted alkyl or an optionally substituted cycloalkyl.

Clause 5. The method of any one of clauses 1-4, wherein R^Z and R^Z′ are the same.

Clause 6. The method of any one of clauses 1-5, wherein the solvent further comprises an organic solvent.

Clause 7. The method of any one of clauses 1-6, wherein the N-heterocyclic carbene catalyst is a compound of formula (I)

wherein

W is S or NR^A

Q¹ is CR^C or N;

Q² is CR^D or N; or

Q¹-Q² is CR^x1R^y1—CR^r2R^y2;

R^A and R^B are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^C, and R^D are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl;

R^A and R^C, R^B and R^D, and/or R^C and R^D alternatively together with the N or C atoms to which they are attached form a ring;

R^B alternatively is an alkylene forming a dimer;

R^x1, R^y1, R^x2, and R^y2 are each independently hydrogen or alkyl; and

X⁻ is counter ion.

Clause 8. The method of clause 7, wherein W is NR^A.

Clause 9. The method of clause 8, wherein

R^A and R^B are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl; and

R^C and R^D are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl.

Clause 10. The method of clause 8, wherein R^A and R^C, R^B and R^D, or R^C and R^D together with the N or C atoms to which they are attached form a ring.

Clause 11. The method of clause 7, wherein Q¹-Q² is CR^x1R^y1—CR^x2R^y2.

Clause 12. The method of clause 11, wherein R^A and R^B are each independently an optionally substituted aryl.

Clause 13. The method of clause 7, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a), (I-b), (I-c), or (I-d)

wherein

G¹ is an optionally substituted heterocycle; and

G² is an optionally substituted aryl.

Clause 14. The method of any one of clauses 7-13, wherein X⁻ is Cl⁻, Br⁻, I⁻, or BF₄⁻.

Clause 15. The method of clause 1 or clause 7, wherein the N-heterocyclic carbene catalyst is selected from the group consisting of

in which Mes is

and Dipp is

Clause 16. The method of clause 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and wherein R^Z is an optionally substituted aryl or an optionally substituted heteroaryl.

Clause 17. The method of clause 16, wherein the N-heterocyclic carbene catalyst is

Clause 18. The method of any one of clauses 16-17, wherein R^Z is

each of which is optionally substituted.

Clause 19. The method of clause 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-c), and wherein R^Z is an optionally substituted alkenyl or an optionally substituted cycloalkenyl.

Clause 20. The method of clause 19, wherein N-heterocyclic carbene catalyst is

Clause 21. The method of any one of clauses 19-20, wherein R^Z is

wherein

R¹ and R² are independently hydrogen, alkyl, aryl, or heteroaryl, wherein the alkyl, aryl, and heteroaryl are optionally substituted; and

R³ is hydrogen, alkyl, or aryl, wherein the alkyl and aryl are optionally substituted, or

R¹ and R³ together with the carbon atoms to which they are attached form a 6- to 8-membered ring, which is optionally substituted.

Clause 22. The method clause 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and wherein R^Z is an optionally substituted alkyl or an optionally substituted cycloalkyl.

Clause 23. The method of clause 22, wherein N-heterocyclic carbene catalyst is

Clause 24. The method of any one of clauses 22-23, wherein R^Z is R^W—(CR^aaR^b)_p—, wherein

R^W is hydrogen, deuterium, —NH(benzyloxycarbonyl), alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, and heterocyclyl are optionally substituted;

R^aa and R^bb at each occurrence are independently hydrogen, deuterium, alkyl, —NH(t-butoxycarbonyl), or —O-benzyl; and

p is 1, 2, 3, 4, 5, 6, 7, or 8.

Clause 25. The method of any one of clauses 1-24, further comprising isolating the produced deuterated aldehyde.

Clause 26. The method of any one of clauses 1-25, wherein in the level of deuterium incorporation of the —C(O)—D moiety is at least 90%.

Clause 27. The method of clause 26, wherein in the level of deuterium incorporation of the —C(O)—D moiety is at least 95%.

Clause 28. A deuterated aldehyde produced by the method of any one of clauses 1-27.

Clause 29. An isolated deuterated aldehyde produced by the method of clause 25.

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Claims

1. A method for preparing a deuterated aldehyde of formula RZ—C(O)—DwhereinRZ is alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocyclyl; wherein the alkyl, alkenyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, and heterocyclyl are each optionally substituted with one or more Ra, and RZ is optionally deuterated;Ra at each occurrence is independently halogen, —CN, —OH, nitro, —O-benzyl, —NH(t-butoxycarbonyl), —NH(benzyloxycarbonyl), alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkyl, alkenyl, alkynyl, alkoxy, —OC(O)-alkyl, —C(O)O-alkyl, —C(O)NH-alkyl, cycloalkyl, aryl, —O-aryl, —C(O)-aryl, heteroaryl, or heterocyclyl is optionally substituted;the method comprising:contacting an aldehyde of formula RZ′—C(O)—H

2. The method of claim 1, wherein RZ is an optionally substituted aryl or an optionally substituted heteroaryl.

3. The method of claim 1, wherein RZ is an optionally substituted alkenyl or an optionally substituted cycloalkenyl.

4. The method of claim 1, wherein RZ is an optionally substituted alkyl or an optionally substituted cycloalkyl.

5. The method of claim 1, wherein RZ and RZ′ are the same.

6. The method of claim 1, wherein the solvent further comprises an organic solvent.

7. The method of claim 1, wherein the N-heterocyclic carbene catalyst is a compound of formula (I)

8. The method of claim 7, wherein W is NRA.

9. The method of claim 8, wherein RA and RB are each independently an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl; andRC and RD are each independently hydrogen, an optionally substituted alkyl, an optionally substituted cycloalkyl, an optionally substituted aryl, an optionally substituted hereoaryl, or an optionally substituted heterocyclyl.

10. The method of claim 8, wherein RA and RC, RB and RD, or RC and RD together with the N or C atoms to which they are attached form a ring.

11. The method of claim 7, wherein Q1-Q2 is CRx1Ry1—CRx2Ry2.

12. The method of claim 11, wherein RA and RB are each independently an optionally substituted aryl.

13. The method of claim 7, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a), (I-b), (I-c), or (I-d)

14. The method of claim 7, wherein X− is Cl−, Br−, I−, or BF4−.

15. The method of claim 1, wherein the N-heterocyclic carbene catalyst is selected from the group consisting of

16. The method of claim 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and wherein RZ is an optionally substituted aryl or an optionally substituted heteroaryl.

17. The method of claim 16, wherein the N-heterocyclic carbene catalyst is

18. The method of claim 16, wherein RZ is

19. The method of claim 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-c), and wherein RZ is an optionally substituted alkenyl or an optionally substituted cycloalkenyl.

20. The method of claim 19, wherein N-heterocyclic carbene catalyst is

21. The method of claim 19, wherein RZ is

22. The method of claim 13, wherein the N-heterocyclic carbene catalyst is a compound of formula (I-a) or (I-c), and wherein RZ is an optionally substituted alkyl or an optionally substituted cycloalkyl.

23. The method of claim 22, wherein N-heterocyclic carbene catalyst is

24. The method of claim 22, wherein RZ is RW—(CRaaRbb)p—, wherein RW is hydrogen, deuterium, —NH(benzyloxycarbonyl), alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, or heterocyclyl, wherein the alkenyl, alkynyl, aryl, —C(O)-aryl, heteroaryl, and heterocyclyl are optionally substituted;Raa and Rbb at each occurrence are independently hydrogen, deuterium, alkyl, —NH(t-butoxycarbonyl), or —O-benzyl; andp is 1, 2, 3, 4, 5, 6, 7, or 8.

25. The method of claim 1, further comprising isolating the produced deuterated aldehyde.

26. The method of claim 1, wherein in the level of deuterium incorporation of the —C(O)—D moiety is at least 90%.

27. The method of claim 26, wherein in the level of deuterium incorporation of the —C(O)—D moiety is at least 95%.

28. A deuterated aldehyde produced by the method of claim 1.

29. An isolated deuterated aldehyde produced by the method of claim 25.