Patent Grant
9670240
The following disclosure relates to novel cyclic phosphinate derivatives and a method of preparing the same, and more particularly, to cyclic phosphinate derivatives including benzoxaphosphole oxide derivatives and benzoxaphosphorin oxide derivatives, and a method of preparing the same.
Heterocyclic compounds configure a basic skeleton of a natural material, and among them, organic phosphorus compounds have pharmacological and physiological activities, such that the organic phosphorus compounds are important compounds in pharmaceutical, material, and crop protection agent fields.
Among them, since benzoxaphosphole oxide compounds have physiological activities and may be used as an important raw material or intermediate in agricultural and material chemistry fields in addition to being used in synthesizing a new medicine, an interest in synthesis methods thereof have increased. Therefore, synthesis methods of benzoxaphosphole oxide derivatives as described above have been reported (Chem. Rev. 2003, 103, 3029). Up to now, the methods of synthesizing benzoxaphosphole oxide have a disadvantage in that benzoxaphosphole oxide is synthesized through several steps.
Meanwhile, a dibenzoxaphosphorin oxide derivative is a lactone derivative including phosphorus. It was known that uses of lactone are various, and various application methods and synthesis methods have been reported (J. Org. Chem. 2007, 72, 9379-9382). In addition, it has been well known that lactone has physiological activities, and since lactone is used as a basic skeleton of a natural material, even in the case in which phosphorus is contained, it is expected that the lactone derivative will have physiological activities or be variously applied through additional steps. However, the number of reported compounds in which phosphorus is contained is small, and particularly, there is no reported compound in which various substituents are contained (Transition Met. Chem. 2008, 33, 505-510). In addition, recently, research into a method of synthesizing a carbon-carbon, carbon-nitrogen, or carbon-oxygen bond by using various transition metal catalysts through a carbon-hydrogen bond activation reaction with a directing group has been conducted. This reaction is characterized in that various bonds may be introduced by interaction between the catalyst and the directing group without pre-functionalization. Recently, it has been reported that various bonds are formed by using a directing group containing phosphorus through the carbon-hydrogen bond activation reaction with a transition metal (Org. Lett. 2013, 15, 3358-3361; Org. Lett. 2013, 15, 3986-3989). In addition, a method of forming a carbon-oxygen bond to synthesize a cyclic compound is a good method of synthesizing a novel heterocyclic compound (Org. Lett. 2013, 15, 5210-5213).
However, the case of synthesizing a benzoxaphosphole oxide derivative and a dibenzoxaphosphorin oxide derivative by using the transition metal catalyst through the carbon-hydrogen bond activation reaction has not yet been reported. Therefore, it is important to develop an efficient C—H bond activation reaction using a directing group associated with phosphorus.
The present invention relates to a new method of synthesizing a benzoxaphosphole oxide derivative and a dibenzoxaphosphorin oxide derivative having a short reaction step. The method of preparing a benzoxaphosphole oxide derivative and a dibenzoxaphosphorin oxide derivative according to the present invention has an advantage in that benzoxaphosphole oxide derivatives and dibenzoxaphosphorin oxide derivatives in which various substituents are introduced by an intramolecular carbon-oxygen coupling reaction due to the carbon (sp2 or sp3)-hydrogen bond activation reaction may be prepared from a phosphinic acid derivative in the presence of a palladium catalyst.
An embodiment of the present invention is directed to providing a novel cyclic phosphinate derivative having pharmacological and physiological activities.
Another embodiment of the present invention is directed to providing a method of preparing a novel cyclic phosphinate derivative.
In one general aspect, there is provided a cyclic phosphinate derivative represented by the following Chemical Formula 1.
In Chemical Formula 1,
R1 to R4 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen, (C6-C20)aryloxy, or tri(C1-C20)alkylsilyl; when X is
Y is O, or when X is O, Y is
R5 is (C1-C20)alkyl, (C1-C20)alkoxy or (C6-C20)aryl;
Z is —CR11R12— or —CR13═CR14—;
R11 and R12 are each independently hydrogen or (C1-C20)alkyl, or are linked to each other by (C1-C7)alkylene to form a spiro ring;
R11 and R12 are linked to each other by —CR21═CR22—CR23═CR24— or -L-CR25═CR26— to form a fused ring;
R21 to R26 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or are linked to a substituent adjacent thereto by (C1-C7)alkylene, (C2-C7)alkenylene, or (C4-C7)alkanedienylene to form a fused ring;
L is O or S; and
alkyl and aryl of R1 to R5 are further substituted with one or more substituents selected from the group consisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.
In another general aspect, there is provided a method of preparing a cyclic phosphinate derivative represented by Chemical Formula 1 characterized by performing an intramolecular carbon-oxygen coupling reaction on a phosphinic acid derivative represented by the following Chemical Formula 6 or 7 in the presence of a palladium (Pd) catalyst, an oxidant, and a base to prepare a cyclic phosphinate derivative represented by the following Chemical Formula 2 or 3.
Hereinafter, the present invention will be described in detail.
Here, technical terms and scientific terms used in the present specification have the general meaning understood by those skilled in the art to which the present invention pertains unless otherwise defined. In addition, repetitive descriptions of the same technical configuration and action as those in the related art will be omitted.
The present invention may provide a cyclic phosphinate derivative represented by the following Chemical Formula 1:
In Chemical Formula 1,
R1 to R4 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen, (C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;
when X is
Y is O, or when X is O, Y is
R5 is (C1-C20)alkyl, (C1-C20)alkoxy or (C6-C20)aryl;
Z is —CR11R12— or —CR13═CR14—;
R11 and R12 are each independently hydrogen, or (C1-C20)alkyl, or are linked to each other by (C1-C7)alkylene to form a spiro ring;
R13 and R14 are linked to each other by —CR21═CR22—CR23═CR24— or -L-CR25═CR26— to form a fused ring;
R21 to R26 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or are linked to a substituent adjacent thereto by (C1-C7)alkylene, (C2-C7)alkenylene, or (C4-C7)alkanedienylene to form a fused ring;
L is O or S; and
alkyl and aryl of R1 to R5 are further substituted with one or more substituents selected from the group consisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.
The terms ┌alkyl┘ and ┌alkoxy┘ disclosed herein include both of the straight chain type and the branched chain type.
The term ┌aryl┘ disclosed herein, which is an organic radical derived from aromatic hydrocarbon by removing one hydrogen atom therefrom, includes a single ring or a fused ring containing, properly 4 to 7 ring atoms, and preferably 5 or 6 ring atoms in each ring, and include forms in which two or more aryls are combined through single bond(s). Specific examples of aryl include aromatic groups such as phenyl, naphthyl, biphenyl, indenyl, fluorenyl, phenanthrenyl, anthracenyl, triphenylenyl, pyrenyl, chrysenyl, and naphthacenyl.
The novel cyclic phosphinate derivative represented by Chemical Formula 1 may include a benzoxaphosphole oxide derivative and a benzoxaphosphorin oxide derivative, and may be, preferably, represented by the following Chemical Formula 2 or 3:
In Chemical Formulas 2 and 3, R1 to R4 and R5 have the same definitions as defined in Chemical Formula 1;
Z is CH2— or —CR13═CR14—;
R11 and R12 are each independently (C1-C20)alkyl, or are linked to each other by (C1-C7)alkylene to form a spiro ring;
R13 and R14 are linked to each other by —CR21═CR22═CR23═C24— or -L-CR25═CR26— to form a fused ring;
R21 to R26 are each independently hydrogen, (C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or R21 to R24 are linked to a substituent adjacent thereto by (C1-C7)alkylene or (C4-C7)alkanedienylene to form a fused ring;
L is O or S; and
alkyl and aryl of R1 to R5 are further substituted with one or more substituents selected from the group consisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.
In detail, in Chemical Formulas 2 and 3, preferably, R1 to R4 may be each independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, trifluoromethyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, phenyl, naphthyl, fluorenyl, chloro, bromo, fluoro, or trimethylsilyl (TMS), phenyl, naphthyl, or fluorenyl of R1 to R4 being further substituted with one or more substituents selected from the group consisting of chloro, bromo, fluoro, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, and trifluoromethyl; R5 may be methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, phenyl, or naphthyl, phenyl or naphthyl of R5 being further substituted with one or more substituents selected from the group consisting of chloro, bromo, fluoro, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, and trifluoromethyl; Z may be —CH2—,
R11 and R12 may be each independently methyl, ethyl, propyl, butyl, pentyl, or hexyl, or be linked to each other by butylene or pentylene to form a Spiro ring; R21 to R26 may be each independently hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, phenyl, naphthyl, chloro, bromo, or fluoro; and L may be O or S.
The cyclic phosphinate derivative according to the present invention may be selected from the following compounds, but is not limited thereto.
Hereinafter, the method of preparing a cyclic phosphinate derivative according to the present invention will be described in detail.
The present invention provides a method of preparing a cyclic phosphinate derivative characterized by performing an intramolecular carbon-oxygen coupling reaction on a phosphinic acid derivative represented by the following Chemical Formula 6 to prepare a cyclic phosphinate derivative represented by the following Chemical Formula 2 in the presence of a palladium (Pd) catalyst, an oxidant, and a base:
In Chemical Formulas 2 and 6,
R1 to R4 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen, (C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;
R5 is (C1-C20)alkyl, (C1-C20)alkoxy, or (C6-C20)aryl;
Z is CH2— or —CR13═CR14—;
R13 and R14 are linked to each other by —CR21═CR22—CR23═CR24— or -L-CR25═CR26— to form a fused ring;
R21 to R26 are each independently hydrogen, (C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or R21 to R24 are linked to a substituent adjacent thereto by (C1-C7)alkylene or (C4-C7)alkanedienylene to form a fused ring;
L is O or S; and
alkyl and aryl of R1 to R5 are further substituted with one or more substituents selected from the group consisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.
In addition, the present invention provides a method of preparing a cyclic phosphinate derivative characterized by performing an intramolecular carbon-oxygen coupling reaction on a phosphinic acid derivative represented by the following Chemical Formula 7 to prepare a cyclic phosphinate derivative represented by the following Chemical Formula 3 in the presence of a palladium (Pd) catalyst, an oxidant, and a base:
In Chemical Formulas 3 and 7,
R1 to R4 are each independently hydrogen, (C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen, (C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;
R5 is (C1-C20)alkyl, (C1-C20)alkoxy, or (C6-C20)aryl;
R11 and R12 are each independently (C1-C20)alkyl, or are linked to each other by (C1-C7)alkylene to form a spiro ring; and
alkyl and aryl of R1 to R5 are further substituted with one or more substituents selected from the group consisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.
The method of preparing a cyclic phosphinate derivative represented by Chemical Formula 2 or 3 according to the present invention is a significantly effective method capable of obtaining a product with high yield and high purity by a simple process under mild conditions in the presence of the palladium (Pd) catalyst, the oxidant, and the base.
The palladium (Pd) catalyst used in the method of preparing a cyclic phosphinate derivative according to the present invention may be one or a mixture of two or more selected from the group consisting of PdCl2, PdBr2, Pd(OAc)2, Pd(dba)2, Pd2(dba)3, Pd2dba3.CHCl3, Pd(PPh3)4, Pd(OTf)2, Pd(OTf).2H2O, Pd(TFA)2, PdCl2(MeCN)2, PdCl2(PPh3)2, Pd(dppf)Cl2 and [PdCl(C3H5)]2. More preferably, Pd(OAc)2 may be used as the palladium (Pd) catalyst.
The palladium (Pd) catalyst used in the method of preparing a cyclic phosphinate derivative according to the present invention may be used in a range of 0.01 to 0.5 equivalents with respect to the phosphinic acid derivative represented by Chemical Formula 6 or 7. More preferably, the palladium (Pd) catalyst may be used in a range of 0.05 to 0.15 equivalents. In the case of using the palladium (Pd) catalyst in the above-mentioned range, the cyclic phosphinate derivative may be prepared with high yield, and in the case in which an amount of the palladium (Pd) catalyst is out of the range, yield and economic efficiency may be deteriorated.
As the oxidant used in the method of preparing a cyclic phosphinate derivative according to the present invention, one or a mixture of two or more selected from the group consisting of copper(I) chloride (CuCl), copper(I) oxide (Cu2O), copper(II) oxide (CuO), copper(II) acetate (Cu(OAc)2), copper triflate (Cu(OTf)2), copper(II) chloride (CuCl2), copper(I) bromide (CuBr), copper(I) iodide (CuI), copper(II) acetylacetonate (Cu(acac)2), silver(II) oxide (Ag2O), silver(I) oxide (AgO), silver acetate (AgOAc), silver(II) carbonate (Ag2CO3), sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), sodium acetate (NaOAc), benzoquinone (BQ), iron(III) chloride (FeCl3), manganese(III) acetate dihydrate (Mn(OAc)3.2H2O), vanadium(V) oxide (V2O5) iodosobenzene diacetate (PhI(OAc)2), bis(trifluoroacetoxy)iodobenzene (PhI(TFA)2), acetyl hypoiodite (IOAc), ozone, oxygen, (PhCO2)2, and 2,2,6,6-tetramethyl-1-piperidinyloxy (free radical, TEMPO) may be used. In view of reactivity and yield, it is most preferable that Ag2CO3, PhI(OAc)2, or a mixture thereof is used as the oxidant.
The oxidant used in the method of preparing a cyclic phosphinate derivative according to the present invention may be used in a range of 0.1 to 5.0 equivalents with respect to the phosphinic acid derivative represented by Chemical Formula 6 or 7. In view of yield and economic efficiency, it is most preferable that 1.0 to 3.0 equivalents of the oxidant is used.
The base used in the method of preparing a cyclic phosphinate derivative according to the present invention may be one or a mixture of two or more selected from the group consisting of potassium phosphate monobasic [KH2PO4], sodium phosphate dibasic dihydrate [Na2HPO4.2H2O], sodium phosphate dibasic [Na2HPO4], sodium carbonate [Na2CO3], sodium phosphate monobasic [NaH2PO4], lithium acetate [LiOAc], lithium carbonate [Li2CO3], sodium acetate [NaOAc], potassium phosphate dibasic [K2HPO4], potassium phosphate tribasic [K3PO4], potassium carbonate [K2CO3], cesium fluoride [CsF], potassium bicarbonate [KHCO3], potassium hydroxide [KOH], potassium fluoride [KF], potassium hexafluorophosphate [KPF6], potassium acetate [KOAc], sodium fluoride [NaF], cesium acetate [CsOAc], cesium pivalate [CsOPiv], lithium hexafluorophosphate [LiPF6], lithium phosphate [Li3PO4], lithium fluoride [LiF], and lithium iodide [LiI]. Preferably, NaOAc, K2HPO4, or KOAc may be used as the base.
The base used in the method of preparing a cyclic phosphinate derivative according to the present invention may be used in a range of 0.5 to 3.0 equivalents with respect to the phosphinic acid derivative represented by Chemical Formula 6 or 7. More preferably, the base may be used in a range of 1.0 to 2.5 equivalents.
In the method of preparing a cyclic phosphinate derivative according to the present invention, a ligand may be further used in order to prepare the cyclic phosphinate derivative represented by Chemical Formula 2, wherein the ligand may be one or a mixture of two or more selected from the group consisting of N-acetyl-L-leucine, Boc-Val-OH [N-(tert-butoxycarbonyl)-L-valine], N-Boc-L-isoleucine, Boc-L-leucine, Ac-Gly-OH [N-acetylglycine], N-Boc-L-isoleucine-hemihydrate, Ac-Ala-OH [N-acetyl-L-alanine], Ac-Phe-OH [N-acetyl-L-phenylalanine], pivalic acid, 2-methyl-2-phenylpropanoic acid, adamantane-1-carboxylic acid, (4-CF3—C6H4)3P, (4-MeO—C6H4)3P, (4-MeO—C6H4)3P, (2,6-di-MeO—C6H3)3P, (2,4,6-tri-MeO—C6H2)3P, Xantphos [4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene], XPhos [2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl], CyJohnphos [(2-Biphenyl)dicyclohexylphosphine], SPhos [2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl], Johnphos [(2-Biphenyl)di-tert-butylphosphine], DPEphos [Bis[(2-diphenylphosphino)phenyl]ether], DPPP [1,3-Bis(diphenylphosphino)propane], DPPE [1,2-Bis(diphenylphosphino)ethane], DPPF [1,1′-Bis(diphenylphosphino) ferrocene], tri-o-tolylphosphine, and tri-2-furylphosphine. Preferably, N-acetyl-L-leucine or (4-MeO—C6H4)3P may be used as the ligand.
The ligand used in the method of preparing a cyclic phosphinate derivative according to the present invention may be used in a range of 0.1 to 1.0 equivalent with respect to the phosphinic acid derivative represented by Chemical Formula 6. More preferably, the ligand may be used in a range of 0.1 to 0.5 equivalents.
As a solvent used in the method of preparing a cyclic phosphinate derivative according to the present invention, a general organic solvent may be used, but it is preferable that 1,4-dioxane, dichloromethane (DCM), dichloroethane (DCE), toluene, acetonitrile (MeCN), nitromethane, tetrahydrofuran (THF), chlorobenzene (PhCl), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), t-butanol (t-BuOH), t-amylalcohol (t-AmOH), xylene, hexafluorobenzene (C6F6), bromobenzene (PhBr), trifluoroacetic acid, benzene, or a mixed solvent thereof is used. More preferably, dichloroethane (DCE), chlorobenzene (PhCl), or t-butanol (t-BuOH) may be used.
In the method of preparing a cyclic phosphinate derivative according to the present invention, any reaction temperature may be possible as long as it is a general temperature used in organic synthesis. However, the reaction temperature may be changed depending on a reaction time, a reactant, and an amount of a starting material, and in order to prevent the reaction time from being increased or a reaction yield from being deteriorated by generation of by-products, a cyclization reaction may be performed in a temperature range of room temperature to 160° C., and preferably 80 to 120° C.
The reaction time may be changed depending on the reactant, the amount of the reactant, and the kind and amount of solvent, and the reaction is terminated after confirming that the phosphinic acid derivative represented by Chemical Formula 6 or 7, which is the starting material, is completely consumed using thin layer chromatography (TLC), or the like. When the reaction is completed, after distilling the solvent under reduced pressure, a target material may be separated and purified by a general method such as column chromatography, or the like.
Hereinafter, configurations of the present invention will be described in detail through Examples, but the following Examples are only to assist in understanding of the present invention. Therefore, the scope of the present invention is not limited thereto.
After Pd(OAc)2 (4.5 mg, 10 mol %, 0.1 eq), (4-MeO—C6H4)3P (28.2 mg, 0.08 mmol), Ag2CO3 (165.4 mg, 0.6 mmol), and K2HPO4 (87.2 mg, 0.5 mmol) were put into a V-vial, 2,6-dimethylphenyl-phosphonic acid monoethyl ester (42.8 mg, 0.2 mmol) as a starting material and PhCL (2.0 mL) as a solvent were added thereto and stirred at 120° C. for 12 hours. After confirming that the starting material was completely consumed using TLC, the resultant was extracted with ethylacetate (5 mL×3) and the reaction was terminated by celite filtration. After removing the solvent, the resultant was separated using column chromatography, thereby obtaining 7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (25.5 mg, 60%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.49 (t, J=7.6 Hz, 1H), 7.26-7.23 (m, 1H), 7.13-7.11 (m, 1H), 5.29-5.16 (m, 2H), 4.22-4.09 (m, 2H), 2.59 (s, 3H), 1.35 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using 2,4,6-trimethylphenyl-phosphonic acid monoethyl ester (45.6 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (36.2 mg, 80%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.06 (d, J=5.8 Hz, 1H), 6.92 (s, 1H), 5.23-5.11 (m, 2H), 4.21-4.03 (m, 2H), 2.54 (s, 3H), 2.39 (s, 3H), 1.34 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using 2,6-dimethyl-4-t-butylphenyl-phosphonic acid monoethyl ester (54.1 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5-tert-butyl-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (34.3 mg, 64%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.26 (d, J=5.8 Hz, 1H), 7.10 (s, 1H), 5.27-5.14 (m, 2H), 4.22-4.06 (m, 2H), 2.57 (s, 3H), 1.35 (d, J=7.1 Hz, 3H), 1.32 (s, 9H)
A reaction was performed by the same method as in Example 1 except for using 2,6-dimethyl-4-methoxyphenyl-phosphonic acid monoethyl ester (48.8 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5-methoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (30.0 mg, 62%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 6.70 (d, J=4.0 Hz, 1H), 6.51 (s, 1H), 5.16-5.03 (m, 2H), 4.12-3.98 (m, 2H), 3.80 (s, 3H), 2.47 (s, 3H), 1.27 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using 2,6-dimethyl-4-phenoxyphenyl-phosphonic acid monoethyl ester (61.3 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5-phenoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (36.5 mg, 60%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.40 (t, J=7.9 Hz, 2H), 7.21 (t, J=7.9 Hz, 1H), 7.06-7.03 (m, 2H), 6.86-6.85 (m, 1H), 6.61 (s, 1H), 5.19-5.07 (m, 2H), 4.22-4.09 (m, 2H), 2.53 (s, 3H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using 2,6-dimethyl-4-trimethylsilylphenyl-phosphonic acid monoethyl ester (57.3 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5-(trimethylsilyl)-7-methyl-1-oxo-1-ethoxy-2, 1-benzoxaphosphole (30.1 mg, 53%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.36 (d, J=6.4 Hz, 1H), 7.25 (d, J=3.0 Hz, 1H), 5.30-5.17 (m, 2H), 4.18-4.11 (m, 2H), 2.59 (s, 3H), 1.35 (t, J=7.1 Hz, 3H), 0.28 (s, 9H)
A reaction was performed by the same method as in Example 1 except for using 2-methyl-6-ethylphenyl-phosphonic acid monoethyl ester (45.6 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 7-ethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (19.5 mg, 43%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.52 (td, J1=11.4, J2=1.2 Hz, 1H), 7.29 (t, J=6.9 Hz, 1H), 7.14-7.11 (m, 1H), 5.29-5.16 (m, 2H), 4.23-4.08 (m, 2H), 2.93 (q, J=7.6 Hz, 2H), 1.34 (t, J=7.7 Hz, 6H)
A reaction was performed by the same method as in Example 1 except for using 2,4-dimethyl-6-t-butylphenyl-phosphonic acid monoethyl ester (51.3 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 7-tert-butyl-5-methyl-1-oxo-1-methoxy-2,1-benzoxaphosphole (28.5 mg, 56%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.29 (d, J=6.8 Hz, 1H), 6.93 (s, 1H), 5.22-5.12 (m, 2H), 3.71 (d, J=11.9 Hz, 3H), 2.41 (s, 3H), 1.51 (s, 9H)
A reaction was performed by the same method as in Example 1 except for using 2,3,5,6-tetramethylphenyl-phosphonic acid monoethyl ester (48.5 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 4,6,7-trimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (25.9 mg, 54%) corresponding to a target compound.
1H NMR (400 MHz, CDCl3) δ 7.15 (s, 1H), 5.18-5.04 (m, 2H), 4.21-4.05 (m, 2H), 2.46 (s, 3H), 2.29 (s, 3H), 2.16 (s, 3H), 1.34 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using 3-bromo-2,4,6-trimethylphenyl-phosphonic acid monoethyl ester (61.4 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 6-bromo-5, 7-dim ethyl-1-oxo-1-ethoxy-2, 1-benzoxaphosphole and 4-bromo-5, 7-dim ethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole at a ratio of 2:1 (38.4 mg, 63%) corresponding to the target compounds.
6-Bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole: 1H NMR (400 MHz, CDCl3) δ 7.04 (d, J=3.4 Hz, 1H), 5.20-5.07 (m, 2H), 4.23-4.07 (m, 2H), 2.64 (s, 3H), 2.49 (s, 3H), 1.35 (t, J=7.1 Hz, 3H)
4-Bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole: 1H NMR (400 MHz, CDCl3) δ 7.15 (d, J=6.7 Hz, 1H), 5.15-5.02 (m, 2H), 4.19-4.09 (m, 2H), 2.51 (s, 3H), 2.44 (s, 3H), 1.35 (t, J=7.0 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using methyl-(2,6-dimethylphenyl)-phosphinic acid (36.8 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 7-methyl-1-oxo-1-methyl-2,1-benzoxaphosphole (29.5 mg, 81%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.48 (t, J=7.6 Hz, 1H), 7.24 (t, J=6.3 Hz, 1H), 7.14 (d, J=7.6 Hz, 1H), 5.46-5.21 (m, 2H), 2.62 (s, 3H), 1.84 (d, J=14.6 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using methyl-(2,4,6-trimethylphenyl)-phosphinic acid (39.6 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5,7-dimethyl-1-oxo-1-methyl-2,1-benzoxaphosphole (34.1 mg, 87%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.05 (d, J=5.0 Hz, 1H), 6.94 (s, 1H), 5.41-5.16 (m, 2H), 2.57 (s, 3H), 2.39 (s, 3H), 1.81 (d, J=14.6 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using methyl-(2,3,5,6-tetramethylphenyl)-phosphinic acid (42.4 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 4,6,7-trimethyl-1-oxo-1-methyl-2,1-benzoxaphosphole (23.5 mg, 56%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.14 (s, 1H), 5.35-5.10 (m, 2H), 2.49 (s, 3H), 2.29 (s, 3H), 2.18 (s, 3H), 1.81 (d, J=14.5 Hz, 3H)
A reaction was performed by the same method as in Example 1 except for using phenyl-(2,6-dimethylphenyl)-phosphinic acid (49.2 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 7-methyl-1-oxo-1-phenyl-2,1-benzoxaphosphole (28.3 mg, 58%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.76-7.70 (m, 2H), 7.58-7.44 (m, 3H), 7.23-7.17 (m, 2H), 5.62-5.39 (m, 2H), 2.36 (s, 3H)
A reaction was performed by the same method as in Example 1 except for using phenyl-(2,4,6-trimethylphenyl)-phosphinic acid (52.1 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 5,7-dimethyl-1-oxo-1-phenyl-2,1-benzoxaphosphole (32.0 mg, 62%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.74-7.69 (m, 2H), 7.56-7.52 (m, 1H), 7.47-7.43 (m, 2H), 7.01-7.00 (m, 2H), 5.56-5.33 (m, 2H), 2.40 (s, 3H), 2.32 (s, 3H)
A reaction was performed by the same method as in Example 1 except for using bis(2,6-dimethylphenyl)-phosphinic acid (54.9 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example 1, thereby obtaining 7-methyl-1-oxo-1-(2,6-dimethylphenyl)-2,1-benzoxaphosphole (12.0 mg, 22%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.46 (td, J1=7.5, J2=1.0 Hz, 1H), 7.31 (td, J1=15.2, J2=1.6 Hz, 1H), 7.20-7.15 (m, 2H), 7.11-7.07 (m, 2H), 5.68-5.33 (m, 2H), 2.43 (s, 6H), 2.28 (s, 3H)
After Pd(OAc)2 (4.5 mg, 10 mol %, 0.1 eq), PhI(OAc)2 (99.6 mg, 0.3 mmol), and NaOAc (16.4 mg, 0.2 mmol) were put into a V-vial, dimethylbenzylphosphonic acid monoethyl ester (45.6 mg, 0.2 mmol) as a starting material and DCE (2.0 mL) as a solvent were added thereto and stirred at 80° C. for 20 hours. After confirming that the starting material was completely consumed using TLC, the resultant was extracted with ethylacetate (5 mL×3) and the reaction was terminated by celite filtration. After removing the solvent, the resultant was separated using column chromatography, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (39.4 mg, 87%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.24-7.16 (m, 2H), 7.11-7.06 (m, 1H), 7.01-6.99 (m, 1H), 4.35-4.26 (m, 2H), 1.52 (dd, J=17.6, 3.9 Hz, 6H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using diethylbenzylphosphonic acid monoethyl ester (51.3 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-diethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (44.2 mg, 87%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.24-7.20 (m, 1H), 7.12-7.05 (m, 2H), 7.01-7.00 (m, 1H), 4.36-4.23 (m, 2H), 2.07-1.18 (m, 4H), 1.35 (t, J=7.4 Hz, 3H), 1.09 (t, J=7.4 Hz, 3H), 0.89 (t, J=7.4 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using dipropylbenzylphosphonic acid monoethyl ester (48.0 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dipropyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (54.2 mg, 96%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.24-7.19 (m, 1H), 7.13-7.11 (m, 1H), 7.08-7.04 (m, 1H), 7.00-6.98 (m, 1H), 4.35-4.21 (m, 2H), 2.00-1.55 (m, 5H), 1.48-1.37 (m, 2H), 1.34 (t, J=7.1 Hz, 3H), 1.21-1.08 (m, 1H), 0.99 (t, J=7.2 Hz, 3H), 0.86 (t, J=7.3 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 2-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-4-methyl-1,2-benzoxaphosphole (28.8 mg, 60%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.10 (t, J=7.9 Hz, 1H), 6.86-6.82 (m, 2H), 4.33-4.26 (m, 2H), 2.40 (s, 3H), 1.61 (dd, J=17.6, 15.1 Hz, 6H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 3-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-5-methyl-1,2-benzoxaphosphole (34.1 mg, 71%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.02-6.97 (m, 2H), 6.89 (d, J=8.1 Hz, 1H), 4.34-4.24 (m, 2H), 2.31 (s, 3H), 1.50 (dd, J=17.6, 3.9 Hz, 6H), 1.35 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-methyl-1,2-benzoxaphosphole (40.4 mg, 84%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.04 (dd, J=7.7, 1.2 Hz, 1H), 6.91-6.88 (m, 1H), 6.82 (s, 1H), 4.34-4.24 (m, 2H), 2.33 (s, 3H), 1.50 (dd, J=17.6, 4.0 Hz, 6H), 1.35 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(t-butyl)-dimethylbenzylphosphonic acid monoethyl ester (56.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-tert-butyl-1,2-benzoxaphosphole (46.9 mg, 83%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.12-7.07 (m, 2H), 7.03 (m, 1H), 4.35-4.26 (m, 2H), 1.50 (dd, J=17.6, 2.8 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H), 1.30 (s, 9H)
A reaction was performed by the same method as in Example 17 except for using 3-(methoxy)-dimethylbenzylphosphonic acid monoethyl ester (51.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-5-methoxy-1,2-benzoxaphosphole (34.9 mg, 68%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 6.93 (d, J=8.4 Hz, 1H), 6.76-6.72 (m, 2H), 4.34-4.24 (m, 2H), 3.78 (s, 3H), 1.51 (dd, J=17.5, 1.5 Hz, 6H), 1.35 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(methoxy)-dimethylbenzylphosphonic acid monoethyl ester (51.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-methoxy-1,2-benzoxaphosphole (35.9 mg, 70%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.05 (dd, J=8.4 Hz, 1.4 Hz, 1H), 6.63 (ddd, J=8.5, 2.5, 0.9 Hz, 1H), 6.58 (dd, J=2.4 Hz, 0.9 Hz, 1H), 4.35-4.25 (m, 2H), 3.78 (s, 3H), 1.49 (dd, J=17.7, 2.7 Hz, 6H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(chloro)-dimethylbenzylphosphonic acid monoethyl ester (52.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-chloro-1,2-benzoxaphosphole (32.8 mg, 63%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.11-7.06 (m, 2H), 7.03-7.03 (m, 1H), 4.36-4.26 (m, 2H), 1.50 (dd, J=17.6, 2.8 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(trifluoromethyl)-dimethylbenzylphosphonic acid monoethyl ester (59.3 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphole (36.5 mg, 62%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.38-7.36 (m, 1H), 7.30-7.28 (m, 1H), 7.26 (s, 1H), 4.40-4.29 (m, 2H), 1.54 (dd, J=17.5, 4.9 Hz, 6H), 1.38 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(trifluoromethyl)-dipropylbenzylphosphonic acid monoethyl ester (70.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dipropyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphole (48.5 mg, 65%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.35-7.33 (m, 1H), 7.26-7.23 (m, 2H), 4.38-4.24 (m, 2H), 2.02-1.57 (m, 5H), 1.46-1.37 (m, 2H), 1.36 (t, J=7.1 Hz, 3H), 1.20-1.10 (m, 1H), 0.98 (t, J=7.2 Hz, 3H), 0.88 (t, J=7.3 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 1-phenylcyclopentylphosphonic acid ethyl ester (50.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3-cyclopentyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (40.4 mg, 80%) corresponding to a target compound.
1H NMR (400 MHz, CDCl3) δ 7.21-7.15 (m, 2H), 7.08-7.04 (m, 1H), 6.98-6.96 (m, 1H), 4.34-4.24 (m, 2H), 2.71-2.60 (m, 1H), 2.46-2.37 (m, 1H), 2.04-1.82 (m, 5H), 1.79-1.66 (m, 1H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 1-phenylcyclohexylphosphonic acid ethyl ester (53.8 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3-cyclohexyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (45.3 mg, 85%) corresponding to a target compound.
1H NMR (400 MHz, CDCl3) δ 7.22-7.15 (m, 2H), 7.08-7.04 (m, 1H), 6.98-6.96 (m, 1H), 4.37-4.27 (m, 2H), 2.25-2.17 (m, 1H), 2.15-2.09 (m, 1H), 2.07-2.00 (m, 1H), 1.90-1.80 (m, 2H), 1.78-1.71 (m, 2H), 1.64-1.45 (m, 2H), 1.39-1.29 (m, 1H), 1.36 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using ethylmethylbenzylphosphonic acid monoethyl ester (48.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3-ethyl-3-methyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (40.4 mg, 84%, diastereomeric ratio=2:1) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) data for the major isomer; δ 7.25-7.19 (m, 1H), 7.15-7.11 (m, 1H), 7.10-7.05 (m, 1H), 7.01-6.99 (m, 1H), 4.36-4.23 (m, 2H), 1.98-1.79 (m, 2H), 1.50 (d, J=17.8 Hz, 3H), 1.37 (t, J=7.1 Hz, 3H), 1.10 (t, J=7.5 Hz, 3H); data for the minor isomer; δ 7.25-7.19 (m, 1H), 7.15-7.11 (m, 1H), 7.10-7.05 (m, 1H), 7.01-6.99 (m, 1H), 4.36-4.23 (m, 2H), 1.98-1.79 (m, 2H), 1.50 (d, J=17.8 Hz, 3H), 1.34 (t, J=7.1, 3H), 0.96 (t, J=7.4 Hz, 3H);
A reaction was performed by the same method as in Example 17 except for using 4-(phenyl)-dimethylbenzylphosphonic acid monoethyl ester (60.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-phenyl-1,2-benzoxaphosphole (45.9 mg, 76%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.98 (s, 1H), 7.58-7.52 (m, 6H), 7.41 (t, J=7.5 Hz, 2H), 7.33-7.30 (m, 1H), 3.81-3.78 (m, 2H), 1.60 (d, J=15.8 Hz, 6H), 1.11 (t, J=6.9 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(3-methylphenyl)-dimethylbenzylphosphonic acid monoethyl ester (63.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methyl)phenyl-1,2-benzoxaphosphole (43.0 mg, 68%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.78 (s, 1H), 7.57-7.52 (m, 4H), 7.41-7.36 (m, 2H), 7.32-7.29 (m, 1H), 7.15-7.13 (m, 1H), 3.81-3.72 (m, 2H), 2.40 (s, 3H), 1.59 (d, J=16.8 Hz, 6H), 1.10 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(4-methylphenyl)-dimethylbenzylphosphonic acid monoethyl ester (63.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methyl)phenyl-1,2-benzoxaphosphole (44.9 mg, 71%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.45-7.43 (m, 2H), 7.30-7.28 (m, 1H), 7.25 (s, 1H), 7.23-7.20 (m, 3H), 4.37-4.28 (m, 2H), 2.39 (s, 3H), 1.55 (dd, J=17.6, 2.6 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(4-t-butylphenyl)-dimethylbenzylphosphonic acid monoethyl ester (72.1 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(4-tert-butyl)phenyl-1,2-benzoxaphosphole (53.0 mg, 74%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.50-7.45 (m, 4H), 7.32-7.30 (m, 1H), 7.22-7.20 (m, 2H), 4.39-4.28 (m, 2H), 1.55 (dd, J=17.6, 2.1 Hz, 6H), 1.37 (t, J=7.0 Hz, 3H), 1.35 (s, 9H)
A reaction was performed by the same method as in Example 17 except for using 4-(3-methoxyphenyl)-dimethylbenzylphosphonic acid monoethyl ester (66.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methoxy)phenyl-1,2-benzoxaphosphole (47.9 mg, 72%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.35 (t, J=7.9 Hz, 1H), 7.33-7.30 (m, 1H), 7.24-7.22 (m, 2H), 7.14-7.12 (m, 1H), 7.07-7.07 (m, 1H), 6.91 (ddd, J=8.2, 2.6, 0.9 Hz, 1H), 4.38-4.28 (m, 2H), 3.86 (s, 3H), 1.55 (dd, J=17.6, 2.6 Hz, 6H), 1.38 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(4-methoxyphenyl)-dimethylbenzylphosphonic acid monoethyl ester (66.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methoxy)phenyl-1,2-benzoxaphosphole (36.6 mg, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.50-7.47 (m, 2H), 7.28-7.26 (m, 1H), 7.21-7.19 (m, 2H), 6.99-6.95 (m, 2H), 4.37-4.28 (m, 2H), 3.85 (s, 3H), 1.55 (dd, J=17.6, 2.4 Hz, 6H), 1.38 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(4-chlorophenyl)-dimethylbenzylphosphonic acid monoethyl ester (67.8 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(4-chloro)phenyl-1,2-benzoxaphosphole (49.8 mg, 74%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.57-7.49 (m, 6H), 7.40-7.37 (m, 2H), 6.84 (s, 1H), 3.82-3.75 (m, 2H), 1.59 (d, J=16.8 Hz, 6H), 1.11 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 17 except for using 4-(3,5-dimethylphenyl)-dimethylbenzylphosphonic acid monoethyl ester (66.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17, thereby obtaining 3,3-dimethyl-2-oxo-2-ethoxy-6-(3,5-dimethyl) phenyl-1,2-benzoxaphosphole (44.9 mg, 68%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.30-7.28 (m, 1H), 7.21-7.19 (m, 1H), 7.15 (s, 2H), 7.00 (s, 1H), 4.37-4.28 (m, 2H), 2.37 (s, 6H), 1.55 (dd, J=17.6, 2.6 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)
After Pd(OAc)2 (4.5 mg, 0.02 mmol), PhI(OAc)2 (128.8 mg, 0.4 mmol), KOAc (39.3 mg, 0.4 mmol), N-acetyl-L-leucine (10.4 mg, 0.06 mmol), 1,1′-biphenylphosphonic acid monomethyl ester (52.4 mg, 0.2 mmol), and t-BuOH (2.5 mL) were put into a V-vial, the V-vial was covered with a cap and the mixture was stirred and heated at 100° C. for 12 hours. After the reactant was extracted with dichloromethane, filtered using celite, and dried over MgSO4, the solvent was concentrated and removed, and the resultant was separated using column chromatography (ethyl acetate:hexane=1:1), thereby obtaining 6-ethoxy-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%).
1H NMR (400 MHz, CDCl3, 25° C., TMS): =8.00-7.93 (m, 3H), 7.74-7.70 (m, 1H), 7.55-7.50 (m, 1H), 7.41-7.37 (m, 1H), 4.26-4.19 (m, 2H), 1.28 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 2′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-1-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3)=8.01 (ddd, J=15.0, 7.5, 1.1 Hz, 1H), 7.84 (t, J=7.2 Hz, 3H), 7.70-7.66 (m, 1H), 7.52-7.48 (m, 1H), 7.28-7.24 (m, 1H), 7.12 (d, J=17.9 Hz, 1H), 4.29-4.14 (m, 2H), 2.70 (s, 3H), 1.25 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3)=8.00-7.93 (m, 2H), 7.72-7.68 (m, 2H), 7.52-7.48 (m, 1H), 7.18 (d, J=8.3 Hz, 1H), 7.12 (d, J=8.3 Hz, 1H), 4.24-4.17 (m, 2H), 2.41 (s, 3H), 1.27 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 4′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg, 0.2 mmol) instead of 1 r-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-3-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.00-7.91 (m, 2H), 7.81 (d, J=8.1 Hz, 1H), 7.70 (t, J=7.8 Hz, 1H), 7.50-7.46 (m, 1H), 7.08 (d, J=8.2 Hz, 1H), 7.05 (s, 1H), 4.25-4.17 (m, 2H), 2.40 (s, 3H), 1.28 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 4′-t-butyl-1,1′-biphenylphosphonic acid monoethyl ester (63.6 mg, 0.2 mmol) instead of 1,1′-′ biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-3-tert-butyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.97-7.92 (m, 2H), 7.85 (d, J=8.4 Hz, 1H), 7.72-7.67 (m, 1H), 7.51-7.46 (m, 1H), 7.29 (dd, J=8.4, 1.8 Hz, 1H), 7.23 (d, J=2.0 Hz, 1H), 4.26-4.19 (m, 2H), 1.35 (s, 9H), 1.29 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 4′-methoxy-1,1′-biphenylphosphonic acid monoethyl ester (58.4 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-3-methoxy-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.95 (ddd, J=14.6, 7.6, 1.1 Hz, 1H), 7.89-7.82 (m, 2H), 7.70-7.66 (m, 1H), 7.47-7.43 (m, 1H), 6.84 (dd, J=8.8, 2.6 Hz, 1H), 6.76 (d, J=2.6 Hz, 1H), 4.26-4.18 (m, 2H), 3.87 (s, 3H), 1.29 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′,4′-dimethoxy-1,1′-biphenylphosphonic acid monoethyl ester (64.4 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 5-ethoxy-2,3-dimethoxy-6H-dibenz[c,e]oxaphosphorin-5-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.95 (ddd, J=14.6, 7.5, 1.0 Hz, 1H), 7.83 (t, J=7.2 Hz, 1H), 7.69 (t, J=7.8 Hz, 1H), 7.48-7.43 (m, 1H), 7.32 (s, 1H), 4.25-4.18 (m, 2H), 3.95 (d, J=14.5 Hz, 6H), 1.29 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 4′-phenyl-1,1′-biphenylphosphonic acid monoethyl ester (67.6 mg, 0.2 mmol) instead of 1 r-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-3-phenyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.02 (m, 3H), 7.75-7.71 (m, 1H), 7.66-7.63 (m, 2H), 7.55-7.46 (m, 5H), 7.43-7.39 (m, 1H), 4.29-4.21 (m, 2H), 1.30 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 2-(naphthalene-2-yl)phenylphosphonic acid monoethyl ester (62.4 mg, 0.2 mmol) instead of L biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 5-ethoxy-5H-benzo[c]naphtho[2,3-e][1,2]oxaphosphorin-5-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.40 (s, 1H), 8.13 (t, J=7.2 Hz, 1H), 8.02 (ddd, J=14.6, 7.5, 1.0 Hz, 1H), 7.90 (d, J=8.1 Hz, 1H), 7.80 (d, J=8.1 Hz, 1H), 7.76-7.73 (m, 1H), 4.28-4.20 (m, 2H), 1.26 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 2-(naphthalene-1-yl)phenylphosphonic acid monoethyl ester (62.4 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 5-ethoxy-5H-benzo[c]naphtho[1,2-e][1,2]oxaphosphorin-5-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.52 (d, J=8.5 Hz, 1H), 8.17 (t, J=7.0 Hz, 1H), 8.08 (ddd, J=14.8, 7.5, 0.8 Hz, 1H), 7.90 (dd, J=14.3, 8.0 Hz, 2H), 7.74 (t, J=7.8 Hz, 1H), 7.60-7.49 (m, 3H), 7.38 (d, J=8.8 Hz, 1H), 4.30-4.15 (m, 2H), 1.22 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 2′-fluoro-1,1′-biphenylphosphonic acid monoethyl ester (56.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-1-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.27 (t, J=7.3 Hz, 1H), 8.04-8.00 (m, 1H), 7.72 (t, J=7.8 Hz, 1H), 7.57-7.52 (m, 1H), 7.09-7.01 (m, 2H), 4.28-4.20 (m, 2H), 1.28 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-chloro-1,1′-biphenylphosphonic acid monoethyl ester (59.2 mg, 0.2 mmol) instead of biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.00 (ddd, J=14.6, 7.6, 1.1 Hz, 1H), 7.94-7.90 (m, 2H), 7.76-7.72 (m, 1H), 7.59-7.52 (m, 1H), 7.36-7.33 (m, 1H), 7.19 (d, J=8.6 Hz, 1H), 4.27-4.20 (m, 2H), 1.29 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 4′-chloro-1,1′-biphenylphosphonic acid monoethyl ester (59.2 mg, 0.2 mmol) instead of 1,1′-biphenyl phosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-3-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 8.00 (ddd, J=14.7, 7.6, 1.0 Hz, 1H), 7.92 (t, J=7.2 Hz, 1H), 7.90 (d, J=9.1 Hz, 1H), 7.75-7.70 (m, 1H), 7.57-7.52 (m, 1H), 7.27-7.25 (m, 2H), 4.29-4.20 (m, 2H), 1.30 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 2-(thiophen-2-yl)phenylphosphonic acid monoethyl ester (53.6 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 5-ethoxy-5-benzo[c]thieno[2,3-e][1,2]oxaphosphorin-5-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.92 (ddd, J=14.1, 7.6, 0.7 Hz, 1H), 7.64-7.60 (m, 1H), 7.51-7.47 (m, 1H), 7.44-7.39 (m, 1H), 7.26-7.25 (m, 1H), 4.27-4.19 (m, 2H), 1.32 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-methyl-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester (58.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2,9-dimethyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.86 (dd, J=14.4, 7.7 Hz, 1H), 7.76 (d, J=6.0 Hz, 1H), 7.71 (d, J=1.5 Hz, 1H), 7.33-7.30 (m, 1H), 7.17 (d, J=8.3 Hz, 1H), 7.10 (d, J=8.2 Hz, 1H), 4.21-4.14 (m, 2H), 2.50 (s, 3H), 2.41 (s, 3H), 1.26 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-methyl-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester (67.2 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2,3-dimethoxy-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.83 (dd, J=14.4, 7.7 Hz, 1H), 7.61 (d, J=6.0 Hz, 1H), 7.31 (s, 1H), 7.28-7.26 (m, 1H), 6.74 (s, 1H), 4.23-4.15 (m, 2H), 3.99 (s, 3H), 3.93 (s, 3H), 2.50 (s, 3H), 1.28 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-chloro-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester (62.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2-chloro-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.90-7.84 (m, 2H), 7.71 (d, J=6.0 Hz, 1H), 7.39-7.36 (m, 1H), 7.17 (d, J=8.7 Hz, 1H), 4.25-4.17 (m, 2H), 2.51 (s, 3H), 1.28 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-methyl-1,1′-biphenyl-4-fluorophosphonic acid monoethyl ester (58.8 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2-methyl-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.98-7.92 (m, 1H), 7.68-7.61 (m, 2H), 7.38 (td, J=12.8, 2.8 Hz, 1H), 7.18 (d, J=8.3 Hz, 1H), 7.12 (d, J=8.3 Hz, 1H), 4.26-4.19 (m, 2H), 2.41 (s, 3H), 1.29 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′,4′-dimethoxy-4-fluoro-1,1′-biphenylphosphonic acid monoethyl ester (68.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2,3-dimethoxy-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.85-7.80 (m, 1H), 7.63 (ddd, J=15.7, 7.6, 2.7 Hz, 1H), 7.38 (td, J=12.8, 2.6 Hz, 1H), 7.26 (s, 1H), 6.75 (s, 1H), 4.28-4.20 (m, 2H), 4.00 (s, 3H), 3.93 (s, 3H), 1.31 (t, J=7.1 Hz, 3H)
A reaction was performed by the same method as in Example 40 except for using 3′-chloro-4-fluoro-1,1′-biphenylphosphonic acid monoethyl ester (62.8 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester of Example 40, thereby obtaining 6-ethoxy-2-chloro-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.
1H NMR (400 MHz, CDCl3) δ 7.94-7.89 (m, 1H), 7.84 (d, J=2.4 Hz, 1H), 7.68 (ddd, J=15.7, 10.2, 2.8 Hz, 1H), 7.42 (td, J=12.8, 2.8 Hz, 1H), 7.36-7.33 (m, 1H), 7.20 (d, J=8.7 Hz, 1H), 4.30-4.22 (m, 2H), 1.31 (t, J=7.1 Hz, 3H)
The cyclic phosphinate derivative according to the present invention may have pharmacological and physiological activities, be used as the basic skeleton of the natural material, and be used as the important raw material or intermediate capable of being used in development of a new drug, synthesis of various medicines, and the crop protection agent field.
In addition, with the method of preparing a cyclic phosphinate derivative according to the present invention, the cyclic phosphinate derivatives in which various substituents are introduced may be prepared with high yield through the simple synthetic process by performing the intramolecular carbon-oxygen coupling reaction on the phosphinic acid derivative in the presence of the palladium (Pd) catalyst, the oxidant, and the base.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2014-0053257 | May 2014 | KR | national |
The present application is a divisional application of U.S. patent application Ser. No. 14/598,143 entitled “Novel Cyclic Phosphinate Derivatives and Method of Preparing the Same,” filed on Jan. 15, 2015, which claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2014-0053257, filed on May 2, 2014, in the Korean Intellectual Property Office, the entire contents of each of which are hereby incorporated by reference in their entirety for all purposes.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4219510 | Miles | Aug 1980 | A |
| Number | Date | Country |
|---|---|---|
| 186747 | Jul 1966 | SU |
| Entry |
|---|
| Ivanov et al. (Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya (1967), (1), 226). Abstract. |
| Ivanov et al. (Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya (1967), (5), 1090-3). Abstract. |
| Tang, W. et al., “New Chiral Phosphorus Ligands for Enantioselective Hydrogenation,” Chemical Reviews, vol. 103, No. 8, Aug. 2003, Published Online Jun. 6, 2003, 42 pages. |
| Thasana, N. et al., “Copper(I)-Mediated and Microwave-Assisted Caryl-Ocarboxylic Coupling: Synthesis of Benzopyranones and Isolamellarin Alkaloids,” Journal of Organic Chemistry, vol. 72, No. 24, Nov. 23, 2007, Published Online Nov. 2, 2007, 4 pages. |
| Keglevich, G. et al., “Platinum(II) complexes of 2-alkoxy-dibenzo[c.e][1,2]oxaphosphorines,” Transition Metal Chemistry, vol. 33, No. 4, May 2008, Published Online Mar. 4, 2008, 6 pages. |
| Seo, J. et al., “Synthesis of Phosphaisocoumarins through Rhodium-Catalyzed Cyclization Using Alkynes and Arylphosphonic Acid Monoesters,” Organic Letters, vol. 15, No. 13, Jul. 5, 2013, Published Online Jun. 21, 2013, 4 pages. |
| Ryu, T. et al., “Rhodium-Catalyzed Oxidative Cyclization of Arylphosphonic Acid Monoethyl Esters with Alkenes: Efficient Synthesis of Benzoxaphosphole 1-Oxides,” Organic Letters, vol. 15, No. 15, Aug. 2, 2013, Published Online Jul. 25, 2013, 4 pages. |
| Eom, D. et al., “Palladium-Catalyzed C(sp2 and sp3)—H Activation/C—O Bond Formation: Synthesis of Benzoxaphosphole 1- and 2-Oxides,” Organic Letters, vol. 15, No. 20, Oct. 18, 2013, Published Online Oct. 8, 2013, 4 pages. |
| Jeong, Y., “Palladium-Catalyszed C(sp2)—H Activation/C—O Bond Formation: Synthesis of Benzoxaphosphole 2-oxide,” Master Thesis, Kangwon National University, Feb. 2014, 121 pages. (Submitted with English Language Abstract). |
| Number | Date | Country | |
|---|---|---|---|
| 20170022229 A1 | Jan 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14598143 | Jan 2015 | US |
| Child | 15286408 | US |
