Patent Application
20160031845
The present invention relates to a process for preparing olefins by means of metathesis in the presence of Ru catalyst complexes generated “in situ”.
Olefin metathesis has become established as an effective carbon-carbon coupling reaction in recent decades and is widely employed in organic synthesis and polymer science. Ruthenium-carbene catalysts, in particular, and their derivatives have firmly anchored olefin metathesis as a versatile and reliable synthetic method in demanding organic synthesis. The extremely wide range of substrates and also great tolerance towards a wide variety of functional groups make olefin metathesis a useful, fast and efficient technique for synthesizing molecules which can otherwise be obtained only with difficulty via traditional organic synthesis. Many different transition metal complexes can serve as catalysts in olefin metathesis. In particular, specific ruthenium- and osmium-carbene compounds are effective catalysts in olefin metathesis reactions such as cross-metathesis (CM), ring-closing metathesis (RCM), ring-opening metathesis (ROM), ring-opening metathesis polymerization (ROMP) or acyclic diene metathesis (ADMET).
Particularly active olefin metathesis catalysts usually bear both phosphane ligands and nucleophilic heterocyclic carbene ligands (NHC ligands) and additionally have a metal-carbene structure. A prominent example of this type of olefin metathesis catalysts are the sometimes commercially available Ru complexes having the general structure RuX2(═CR2)LL′, where X is an anionic ligand, R is selected from the group consisting of hydrogen, (C6-C14)-aryl and (C3-C14)-heteroaryl radicals and L and L′ are each an uncharged electron donor ligand, where L is an N-heterocyclic carbene and L′ is a phosphane.
The synthesis of these ruthenium-carbene complexes is comparatively complicated, raw materials-intensive and expensive. Typical synthetic methods consist of a plurality of stages, with complicated process conditions under an inert gas atmosphere, starting materials which are not readily available or the use of reactants which are problematic in terms of safety sometimes being required. In particular, the use of carbene precursors, e.g. disubstituted cyclopropenes (WO 93/20111), diazoalkanes (WO 97/06185) or acetylenes (DE 19854869), represent a considerable safety risk on an industrial scale and should consequently be avoided. Metal-organic starting materials such as RuCl2(PPh3)3 (Hill et al., Dalton 1999, 285-291) or RuHCl (PPh3)3 (Hoffmann et al., Journal of Organometallic Chemistry 2002, 641, 220-226) are prepared from RuCl3 using a large excess of triphenylphosphane (PPh3), with these PPh3 ligands being lost as a result of a ligand exchange reaction in the subsequent catalyst synthesis. The most recent synthesis improvements can partly compensate for this disadvantage by direct reaction of tricyclohexylphosphane with ruthenium chloride hydrate or Ru(cod)Cl2 to form the (PCy3)2RuCl2-carbene complexes (WO 2009/124977). However, large amounts of PCy3 or PCy3 solution continue to be required. In addition, one of these PCy3 ligands is replaced by an uncharged electron donor ligand in the synthesis of the 2nd generation of ruthenium-carbene complexes, as a result of which PCy3 is once again lost from the complex. Inexpensive alternatives to ruthenium-phosphane complexes are neutral or anionic ruthenium-aryl complexes having the general structure [RuX(═C═[C]n═CR2)L1L2]Y (EP0921129A1). X and R are defined as described above, the ligands Y are anionic, weakly coordinating ligands, the ligands L1 are phosphanes, phosphites, phosphonites, phosphinites, arsanes or stibines, L2 is benzene or a substituted benzene derivative such as p-cymene. Another disadvantage is that the structural unit Ru═C=[C]n═CR2 is relevant for the activity of the ruthenium-aryl complexes, and this in turn requires the use of hazardous, difficult-to-obtain or very sensitive carbene precursors.
Many examples of catalytic systems generated “in situ” from available ruthenium precursors have already been described as an alternative approach. However, to produce the active catalyst, use is made of either
It has also been reported that homobimetallic Ru—NHC complexes can initiate ring-opening metathesis without photochemical or chemical activation (X. Sauvage, Y. Borguet, A. F. Noels, L. Delaude, A. Demonceau, Adv. Synth. Catal. 2007, 349, 255-265). This gives a mixture of cycloisomerization and RCM products when α,ω-dienes are reacted in the presence of these complexes.
It is therefore an object of the present invention to provide a process for preparing olefins by means of metathesis, in which the catalyst should be generated “in situ” from inexpensive ruthenium compounds and the olefin but the above-described activating agents are dispensed with.
The object is achieved by a process for preparing olefins by means of metathesis, which comprises the following steps
For the purposes of the present invention, the term olefin relates to all types of olefins regardless of whether they are monoolefins or diolefins, cyclic olefins or acyclic internal olefins or acyclic terminal olefins or else mixtures of olefins.
An acyclic internal olefin is an olefin whose C—C double bond is not located on the alpha-carbon.
A terminal olefin is an olefin whose C—C double bond is located on the alpha-carbon.
A diolefin is an olefin having two C—C double bonds in a molecule, with a terminal diolefin having the C—C double bonds on the alpha- and omega-carbon atoms and an internal diolefin having the C—C double bonds neither on the alpha-carbon atom nor on the omega-carbon atom. The olefins can also be substituted. Examples of olefins are the monoolefins and diolefins of the general formulae (a)-(g), where n can independently be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 and from 1 to 4 carbon atoms may each be replaced by a heteroatom selected from the group consisting of N, O, 5, P and Si and the hydrogen atoms of the radicals (CnH2n)/(CnH2n+1), NH, PH, POH and SiH2 may be substituted.
The substituents of the olefins are selected from the group consisting of
—{C1-C20}-alkyl,
—{C3-C8}-cycloalkyl,
—{C3-C7}-heterocycloalkyl,
—{C6-C14}-aryl,
—{C3-C14}-heteroaryl,
—{C6-C14}-aralkyl,
—{C1-C20}-alkyloxy,
—{C6-C14}-aryloxy,
—{C6-C14}-aralkyloxy,
—{C1-C20}-alkylthio,
—{C6-C14}-arylthio,
—{C6-C14}-aralkylthio,
—{C1-C20}-acyl,
—{C1-C8}-acyloxy,
—NH({C1-C20}-alkyl),
—NH({C6-C14}-aryl),
—NH({C6-C14}-aralkyl),
—NH({C1-C8}-acyl),
—NH({C1-C8}-acyloxy)
—N((C1-C20)-alkyl)2,
—N({C6-C14}-aryl)2,
—N({C6-C14}-aralkyl)2,
—N({C1-C20}-alkyl)({C6-C14}-aryl),
—N({C1-C8}-acyl)2,
—NH({C1-C20}-alkyl)2+,
—NH({C6-C14}-aryl)2+,
—NH({C6-C14}-aralkyl)2+,
—NH({C1-C20}-alkyl)({C6-C14}-aryl)+,
—N({C6-C14}-aryl)x({C1-C20}-alkyl)3−x+,
—O—C(O)—O—{C1-C20}-alkyl,
—O—C(═O)—O—{C6-C14}-aryl,
—O—C(═O)—O—{C6-C14}-aralkyl,
—NH—C(═O)—O—{C1-C20}-alkyl,
—NH—C(═O)—O—{C6-C14}-aryl,
—NH—C(═O)—O—{C6-C14}-aralkyl,
—O—C(═O)—NH—{C1-C20}-alkyl,
—O—C(═O)—NH—{C6-C14}-aryl,
—O—C(═O)—NH—{C6-C14}-aralkyl,
—NH—C(═O)—NH—{C1-C20}-alkyl,
—NH—C(═O)—NH—{C6-C14}-aryl,
—NH—C(═O)—NH—{C6-C14}-aralkyl,
-halogen,
—C(═N—{C1-C20}-alkyl)-{C1-C20}-alkyl,
—C(═N—{C6-C14}-aryl)-{C1-C20}-alkyl,
—C(═N—{C1-C20}-alkyl)-{C6-C14}-aryl,
—C(═N—{C6-C14}-aryl)-{C6-C14}-aryl,
—SO2—O—{C1-C20}-alkyl,
—SO2—O—{C6-C14}-aryl,
—SO2—O—{C6-C14}-aralkyl,
—SO2—{C1-C20}-alkyl,
—SO2—{C6-C14}-aryl,
—SO2—{C6-C14}-aralkyl,
—SO—{C1-C20}-alkyl,
—SO—{C6-C14}-aryl,
—SO—{C6-C14}-aralkyl,
—Si({C1-C20}-alkyl)3,
—Si({C6-C14}-aryl)3,
—Si({C6-C14}-aryl)x ({C1-C20}-alkyl)3−x,
{C1-C20}-perfluoroalkyl,
—PO(O—{C1-C20}-alkyl)2,
—PO(O—{C6-C14}-aryl)2,
—PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl),
—PO({C1-C20}-alkyl)2,
—PO({C6-C14}-aryl)2,
—PO({C1-C20}-alkyl)({C6-C14}-aryl).
Examples of monoolefins and diolefins are the following compounds
where R is (C1-C18)-alkyl or (C6-C12)-aryl and the olefins may be unsubstituted or substituted as described above.
Preference is given to using terminal monoolefins or terminal diolefins which may be unsubstituted or substituted as described above.
The olefins are particularly preferably selected from the group consisting of the following compounds, which may be unsubstituted or substituted as described above.
For the purposes of the present invention, anionic ligands are singularly or multiply negatively charged ligands which are selected independently from the group consisting of halide, pseudohalide, tetraphenylborate, hexahalophosphate, methanesulphonate, trihalomethanesulphonate, arylsulphonate, alkoxide, aryloxide, carboxylate, sulphate and phosphate. Pseudohalides are ligands which behave chemically similarly to the halides; among the pseudohalides, preference is given to cyanide (CN−), cyanate (OCN−), thiocyanate or (SCN−). Preference is given to anionic ligands selected independently from the group consisting of the halides fluoride, chloride, bromide and iodide, with chloride being particularly preferred.
For the purposes of the present invention, uncharged i-bonding ligands are monocyclic and polycyclic arenes which may also have substituents which may be identical or nonidentical, where the substituents are selected from the group consisting of (C1-C20)-alkyl, (C6-C14)-aryl, (C1-C20)-alkyloxy, (C6-C14)-aryloxy, (C1-C20)-perfluoroalkyl, (C1-C20)-alkylthio, (C2-C10)-alkenylthio, (C2-C10)-alkenyl, (C2-C10)-alkynyl, (C2-C10)-alkenyloxy, (C2-C10)-alkynyloxy, and halogen. The substituents can in turn likewise be substituted, where these substituents are selected from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(P—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl). Examples are benzene, toluene, xylene, cymene, trimethylbenzene, tetramethylbenzene, hexamethylbenzene, tetrahydronaphthalene, and naphthalene. The uncharged i-bonding ligand is particularly preferably selected from the group consisting of benzene, cymene and hexamethylbenzene.
For the purposes of the present invention, an uncharged electron donor ligand is a ligand which does not have a net charge and makes available free electron pairs or electron-filled orbitals for a coordinate bond to an acceptor. An acceptor is an atom which can take up free electrons or electrons from a filled orbital from the donor. Donors are typically main group elements of groups 13-17 of the Periodic Table of the Elements, e.g. C, N, P. Even carbon can occur as uncharged electron donor. Carbon most frequently occurs as uncharged electron donor in carbenes, where the carbon atom bears an electron pair in an orbital. These electrons are available for a sigma-bond to an acceptor atom. Acceptors are typically metal atoms such as Pd(0), Pd(II), Ru (I) or Ru(II). Typical examples of uncharged electron donor ligands are heterocyclic carbenes, phosphanes, phosphinites, phosphonites, phosphites, arsanes and nitrogen bases.
The uncharged electron donor ligand is particularly preferably selected from the group consisting of phosphanes and N-heterocyclic carbenes. Preference is given to N-heterocyclic carbenes selected from the group consisting of compounds of the formulae VI-XI and phosphanes selected from the group consisting of P(phenyl)3 and P(cyclohexyl)3.
For the purposes of the present invention, a heterocyclic carbene is a carbene of the general formula (V)
where
R and R′ are identical or different and are selected from the group consisting of
hydrogen,
(C1-C18)-alkyl,
(C3-C8)-cycloalkyl,
(C3-C7)-heterocycloalkyl,
(C6-C14)-aryl,
and (C3-C14)-heteroaryl;
X and Y are selected independently from the group consisting of carbon, nitrogen and phosphorus atoms and
A is a (C2-C4)-alkylene bridge or a (C2-C4)-heteroalkylene bridge.
Examples of heterocyclic carbenes are the N-heterocyclic carbenes of the formulae VI to XI:
N-heterocyclic carbenes can be obtained in situ by thermal activation of carbene adducts or the combination of an N-heterocyclic carbene precursor and a base. As base, it is possible to use any inorganic or organic base, with preference being given to using nitrogen bases or an alkyloxy base. Particular preference is given to alkyloxy bases which are selected from the group consisting of sodium and potassium salts of methoxide, ethoxide, propoxide and butoxide and isomers thereof. Typical examples of carbene adducts are adducts of N-heterocyclic carbenes with alcohols, chloroform, pentafluorophenol, CO2 and borane.
For the purposes of the present invention, phosphanes are compounds of the general formula PR1R2R3,
where R1, R2 and R3 can be identical or different and can be selected from the group consisting of H, (C1-C18)-alkyl, (C3-C8)-cycloalkyl, (C2-C7)-heterocycloalkyl, (C6-C14)-aryl and (C3-C14)-heteroaryl, where the radicals R1, R2 and R3 can optionally have one or more cyclic structures. Typical examples are P(phenyl)2, P(cyclohexyl)2, P(isopropyl)2, P(cyclopentyl)2, P(tert-butyl)2, P(neopentyl)2, with particular preference being given to P(phenyl)3, P(cyclohexyl)3 and P(isopropyl)3.
For the purposes of the present invention, phosphinites are compounds of the general formula PR1′R2′(OR3′), where R1′ and R2′ can be identical or different and can be selected from the group consisting of (C1-C18)-alkyl, (C3-C8)-cycloalkyl, (C2-C7)-heterocycloalkyl, (C6-C14)-aryl and (C3-C14)-heteroaryl and R3′ can be selected from the group consisting of H, (C1-C8-alkyl, (C6-C14)-aryl, where the radicals R1, R2 and R3′ can optionally have one or more cyclic structures. Typical examples are (tert-butyl)2P(Obutyl), (1-adamantyl)2P(Obutyl), Ph2P(OEt), Ph2P(OPh), P(OPh)2, Ph2P(O-(2,4-di-tert-butyl)phenyl).
For the purposes of the present invention, phosphonites are compounds of the general formula P(OR1″)(OR2″)R3″, where R1″ and R2″ can be identical or different and can be selected from the group consisting of (C1-C8)-alkyl, (C6-C14)-aryl, and R3″ can be selected from the group consisting of H, (C1-C18)-alkyl, (C3-C8)-cycloalkyl, (C2-C7)-heterocycloalkyl, (C6-C14)-aryl and (C3-C14)-heteroaryl, where the radicals R1″, R2″ and R3″ can optionally have one or more cyclic structures. Typical examples are MeP(OMe)2, EtP(OEt)2, PhP(OEt)2, PhP(OPh)2, PhCH2P(OPh)3 and PhP(O-(2,4-di-tert-butyl)phenyl)2.
For the purposes of the present invention, phosphites are compounds of the general formula P(OR1′″)(OR2′″)(OR3′″), where R1′″, R2′″ and R3′″ can be identical or different and can be selected from the group consisting of H, (C1-C8)-alkyl, (C6-C14)-aryl, where the radicals R1′″, R2′″ and R3′″ can optionally have one or more cyclic structures. Typical examples are P(Omethyl)3, P(Oethyl)3, P(Ophenyl)3, P(O-(2,4-di-tert-butyl)phenyl)3 and
For the purposes of the present invention, arsanes are compounds of the general formula AsR1″″R2″″R3″″, where R1″″, R2″″ and R3″″ can be identical or different and can be selected from the group consisting of H, (C1-C18)-alkyl, (C3-C8)-cycloalkyl, (C2-C7)-heterocycloalkyl, (C6-C14)-aryl and (C3-C14)-heteroaryl, where the radicals R1, R2 and R3 can optionally have one or more cyclic structures. Typical examples are As(phenyl)3, As(cyclohexyl)3, As(isopropyl)3, As(cyclopentyl)3, As(tert-butyl)3, As(neopentyl)3, with particular preference being given to As(phenyl)3r As(cyclohexyl)3 and As(isopropyl)3.
For the purposes of the present invention, nitrogen bases are amines and nitrogen aromatics. Examples of amines are ammonia, triethylamine, N,N-dimethylaniline, piperidine, N-methyl-pyrrolidine, 1,4-diazabicyclo[2.2.2]octane or 1,8-diazobicyclo[5.4.0]undec-7-ene, with particular preference being given to triethylamine. Examples of nitrogen aromatics are pyridine, pyrimidine, pyrazine, pyrrole, indole, carbazole, imidazole, pyrazole, benzimidazole, oxazole, triazole, isoxazole, isothiazole, triazole, quinoline, isoquinoline, acridine, phenazine, phenoxazine, phenothiazine or triazine, with particular preference being given to pyridine.
For the purposes of the present invention (C1-Cn)-alkyl is defined as a linear or branched C1-Cn-alkyl group having from 1 to n carbon atoms. Typical examples of C1-Cn-alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonanyl, decanyl, dodecanyl, or octadecanyl including all their structural isomers. A (C1-Cn)-alkyl group can also be substituted by at least one substituent, with the substituents preferably being selected independently from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl).
For the purposes of the present invention, (C3-Cn)-cycloalkyl is a cyclic alkyl group having from 3 to n carbon atoms, with monocyclic, bicyclic and tricyclic alkyl groups being encompassed. Typical examples are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl. A (C1-Cn)-cycloalkyl group can also be substituted by at least one substituent, with the substituents being selected independently from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl).
For the purposes of the present invention, (C2-Cn)-heterocycloalkyl is a cyclic alkyl group having from 2 to n carbon atoms, with monocyclic, bicyclic and tricyclic alkyl groups being encompassed, in which 1 or 2 carbon atoms of the rings have each been replaced by a heteroatom selected from the group consisting of N, O and S. (C2-Cn)-heterocycloalkyl group can also be substituted by at least one substituent, with the substituent being selected independently from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl). Typical examples are 2- or 3-tetrahydrofuryl, 1-, 2- or 3-pyrrolidinyl, 1-, 2-, 3- or 4-piperidinyl, 1-, 2-, or 3-morpholinyl, 1-, or 2-piperazinyl, 1-caprolactyl.
For the purposes of the present invention, (C6-Cn)-aryl is a cyclic aromatic group having from 6 to n carbon atoms. In particular, this includes compounds such as phenyl, naphthyl, anthryl, phenanthryl, biphenyl radicals or systems of the above-described type fused onto the molecule concerned, e.g. indenyl systems. A (C6-Cn)-aryl group can also be substituted by at least one substituent, with the substituents being selected independently from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C3)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl).
For the purposes of the present invention, (C3-Cn)-heteroaryl is a five-, six- or seven-membered aromatic ring system having from 3 to n carbon atoms, where from 1 to 3 carbon atoms of the ring system have each been replaced by a heteroatom selected from the group consisting of N, O and S. Such heteroaryl groups are, in particular, groups such as 2-, 3-furyl, 2-, 3-pyrrolyl, 2-, 3-thienyl, 2-, 3-, 4-pyridyl, 2-, 3-, 4-, 5-, 6-, 7-indolyl, 3-, 4-, 5-pyrazolyl, 2-, 4-, 5-imidazolyl, acridinyl, quinolinyl, phenanthridinyl, 2-, 4-, 5-, 6-pyrimidinyl. A (C3-Cn)-heteroaryl group can also be substituted by at least one substituent, with the substituents being selected independently from the group consisting of halogen, (C1-C8-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl).
For the purposes of the present invention, (C6-Cn)-aralkyl is a group which contains both an alkyl group and an aryl group and has a total of from 6 to n carbon atoms. The aralkyl group can be bound via any of its carbon atoms to the molecule bearing this group. A (C6-Cn)-aralkyl group can also be substituted by at least one substituent, with the substituents being selected independently from the group consisting of halogen, (C1-C8)-alkyl, (C1-C8)-alkyloxy, —NH2, —NO, —NO2, NH(C1-C8)-alkyl, —N((C1-C8)-alkyl)2, —OH, —CF3, —CnF2n+1 (where n is an integer from 2 to 5), NH(C1-C8)-acyl, —N((C1-C8)-acyl)2, (C1-C8)-acyl, (C1-C8)-acyloxy, —SO2—(C1-C8)-alkyl, —SO2—(C6-C14)-aryl, —SO—(C1-C8)-alkyl, —SO—(C6-C14)-aryl, —PO(O—{C1-C20}-alkyl)2, —PO(O—{C6-C14}-aryl)2, —PO(O—{C1-C20}-alkyl)(O—{C6-C14}-aryl), —PO({C1-C20}-alkyl)2, —PO({C6-C14}-aryl)2, —PO({C1-C20}-alkyl)({C6-C14}-aryl).
For the purposes of the present invention, (C2-Cn)-alkylene is a divalent linear (C2-Cn)-alkyl group having from 2 to n carbon atoms. Typical examples are ethylene, n-propylene, isopropylene, n-butylene, isobutylene, tert-butylene, n-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, n-decylene. The (C2-Cn)-alkylene group can also have substituents selected from the group consisting of (C1-C20)-alkyl, (C6-C14)-aryl, (C2-C10)-alkenyl. In addition, the (C2-Cn)-alkylene group can be unsaturated, in which case the unsaturated section can be part of an aromatic or heteroaromatic system.
For the purposes of the present invention, (C2-Cn)-heteroalkylene is a divalent linear (C2-Cn)-alkyl group having from 2 to n carbon atoms, where 1 or 2 carbon atoms have been replaced by heteroatoms such as N, O, S. The (C2-Cn)-heteroalkylene group can also have substituents selected from the group consisting of (C1-C20)-alkyl, (C6-C14)-aryl, (C2-C10)-alkenyl. In addition, the (C2-Cn)-heteroalkylene group can be unsaturated, in which case the unsaturated section can be part of an aromatic or heteroaromatic system.
For the purposes of the present invention, (C2-Cn)-alkenyl is defined as a linear or branched (C2-Cn)-alkyl group having from 2 to n carbon atoms, with the proviso that it has a C—C double bond.
For the purposes of the present invention, (C2-Cn)-alkynyl is defined as a linear or branched (C2-Cn)-alkyl group having from 2 to n carbon atoms, with the proviso that it has a C—C triple bond.
For the purposes of the present invention, (C1-Cn)-alkyloxy is defined as a linear or branched C1-Cn-alkyl group having from 1 to n carbon atoms, with the proviso that it is bound via an oxygen atom to the molecule bearing this group.
For the purposes of the present invention, (C2-Cn)-alkenyloxy is defined as a linear or branched C2-Cn-alkenyl group having from 2 to n carbon atoms, with the proviso that it is bound via an oxygen atom to the molecule bearing this group.
For the purposes of the present invention, (C2-Cn)-alkynyloxy is defined as a linear or branched C2-Cn-alkynyl group having from 2 to n carbon atoms, with the proviso that it is bound via an oxygen atom to the molecule bearing this group.
For the purposes of the present invention, (C1-Cn)-acyl is a group having the general structure R—(C═O)— and a total of from 1 to n carbon atoms, where R is selected from the group consisting of H, (C1-Cn−1)-alkyl, (C1-Cn−1)-alkenyl, (C6-Cn−1)-aryl, (C6-Cn−1)-heteroaryl and (C2-Cn−1)-alkynyl.
For the purposes of the present invention, (C1-Cn)-acyloxy is a group having the general structure R—(C═O)O— and a total of from 1 to n carbon atoms, where R is selected from the group consisting of H, (C1-Cn−1)-alkyl, (C1-Cn−1)-alkenyl, (C6-Cn−1)-aryl, (C6-Cn−1)-heteroaryl and (C2-Cn−1)-alkynyl.
For the purposes of the present invention, a noncoordinating salt is an inorganic salt selected from the group consisting of a sodium, potassium, caesium, barium, calcium or magnesium salt of PF6−, BF4−, BH4−, F3CSO3−, H3CSO3−, ClO4−, SO42−, HSO4−, NO3−, PO43−, HPO42−, H2PO4−, CF3COO−, B(C6F5)4−, B[3,5-(CF3)2C6H3]4−, RSO3− and R′COO−, where R, R′ are selected independently from the group consisting of (C1-C20)-alkyl and (C6-C14)-aryl. R is preferably selected from the group consisting of methyl, phenyl, p-tolyl and p-nitrophenyl, and R′ is preferably selected from the group consisting of H, methyl, phenyl, p-tolyl and p-nitrophenyl.
The noncoordinating salt is preferably selected from the group consisting of a sodium, potassium, caesium, barium, calcium or magnesium salt of PF6−, BF4−, F3CSO3−, CF3COO−, B(C6F5)4−; the noncoordinating salt is particularly preferably NaPF6 or KPF6.
For the purposes of the present invention, a Lewis acid is a compound selected from the group consisting of aluminium, boron, chromium, cobalt, iron, copper, magnesium, lanthanum, magnesium, nickel, palladium and zinc salts of Cl—, Br—, I—, PF6—, BF4—, CF3COO—, B(C6F5)4—, B[3,5-(CF3)2C6H3]4—, RxCOO—, (RyCOCHCORz)—, where Rx, Ry, Rz are selected independently from the group consisting of (C1-C20)-alkyl and (C6-C14)-aryl. Rx, Ry, Rz are preferably selected independently from the group consisting of methyl and phenyl. The Lewis acid is particularly preferably selected from the group consisting of aluminium and iron salts of Cl—, MeCOO— or (MeCOCHCOMe)-, with particular preference being given to aluminium(III) chloride, iron(II) acetate and iron(III) acetylacetonate.
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
For the purposes of the present invention, a halogen compound is a compound selected from the group consisting of salt-like halides and organic halogen compounds. Salt-like halides are selected from the group consisting of lithium, sodium, potassium, caesium, magnesium, calcium and ammonium halides, where ammonium halides are compounds of the general formula [NHx{(C1-C20)-alkyl)4−x]+[halide]− and the halides are selected from the group consisting of chloride, bromide and iodide. An organic halogen compound is a monohalogenated or dihalogenated (C1-C20)-alkyl, (C3-C10)-cycloalkyl, (C6-C14)-aryl or (C1-C20)-aralkyl compound, where the halogens are selected independently from the group consisting of chlorine, bromine and iodine. The organic halogen compound is preferably selected from the group consisting of monobromo and dibromo compounds, aromatic 1,2-organodihalides and allylic monobromides. The salt-like halide is preferably selected from the group consisting of sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide and tetraalkylammonium bromides. The halogen compound is preferably selected from the group consisting of potassium iodide, potassium bromide, tetrabutylammonium bromide, 1,2-dibromocyclohexane, 1,2-bromocyclohexane, 1,2-dibromoethane, 1,2-dibromo-4,5-dimethylbenzene, 1,2-diiodobenzene, 1-bromo-2-iodobenzene, 2-bromostyrene, (2-bromoethyl)benzene and (3-bromopropyl)benzene.
The olefin metathesis reactions are usually carried out by bringing an olefin or an olefin mixture into contact with a ruthenium compound of the general formula (I), adding a Lewis acid or adding a Lewis acid and an anionic, noncoordinating salt and optionally adding a halogen compound and subsequently heating the reaction mixture until the reaction is complete, so that the catalytically active ruthenium compound is formed “in situ”. The reaction temperature is in the range from 30° C. to 140° C., preferably in the range from 40° C. to 140° C., more preferably in the range from 60° C. to 100° C. and particularly preferably in the range from 70° C. to 100° C.
The reaction time is not critical and is in the range from a few minutes to some hours, preferably in the range from 30 minutes to 3 hours.
The reactions are generally carried out under a protective gas atmosphere, preferably under nitrogen or argon, although the presence of oxygen can be tolerated under particular circumstances. The reactions can, under particular circumstances, be carried out in the presence of water. The metathesis reactions can be carried out in all solvents or solvent mixtures which do not deactivate the catalyst. Preference is given to selecting aprotic solvents having little tendency to coordinate. If the olefin is liquid, the reaction can be carried out without a solvent. Solvents are preferably selected from the group consisting of dichloromethane, 1,2-dichlorethane, benzene, toluene, xylene, halobenzene and hexane.
In metathesis reactions the ratio of ruthenium compound to olefin is not critical and is in the range from 1:10 to 1:1 000 000. In the ring-closing metathesis reaction, the ratio of ruthenium compound to olefin is preferably in the range from 1:100 to 1:10 000. In the cross-metathesis reaction, the ratio of ruthenium compound to olefin is preferably in the range from 1:10 to 1:100 and in the ring-opening polymerization metathesis reaction the ratio of ruthenium compound to olefin is preferably in the range from 1:1000 to 1:1 000 000.
The ratio of ruthenium compound to anionic, noncoordinating salt is in the range from 1:1 to 1:10; the ratio is preferably in the range from 1:1 to 1:5 and particular preference is given to a ratio of 1:5.
The ratio of ruthenium compound to Lewis acid is in the range from 1:1 to 1:10; the ratio is preferably in the range from 1:1 to 1:5 and particular preference is given to a ratio of 1:5.
The ratio of ruthenium compound to halogen compound is in the range from 1:1 to 1:333; the ratio is preferably in the range from 1:1 to 1:33.
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
Preferred ruthenium compounds of the general formula (II) are shown in Table 1.
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
Preferred ruthenium compounds of the general formula (III) are shown in Table 2.
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
The invention further provides a process for preparing olefins by means of metathesis, which comprises the following steps
Preferred ruthenium compounds of the general formula (IV) are shown in Table 3.
The invention further provides for the use of the process in metathesis reactions selected from the group consisting of cross-metathesis (CM), ring-closing metathesis (RCM), ring-opening metathesis (ROM), ring-opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET). Preference is given to ring-closing metathesis (RCM) and cross-metathesis (CM).
In contrast to the ruthenium and osmium complexes described in EP0921129A1 for olefin metathesis, no isolation of the ionic complexes and also no metal-carbene unit of the general formula M=C(═C)n═CR1R2 are necessary in the present inventive process in order to achieve activity of the ruthenium compound. The use of alkynols such as the toxic propargyl alcohol can therefore be dispensed with in the olefin metathesis process of the invention. In addition, no activating agents such as photochemical activation, disubstituted cyclopropenes, diazoalkanes or alkynes are necessary to achieve activity of the ruthenium compound.
Furthermore, it is possible to use the ruthenium compound in an amount of less than 1 mol %, based on the olefin.
The following ruthenium compounds were used for the metathesis reactions:
The examples below serve to illustrate the process of the invention without restricting it thereto.
The reactions and the production of stock solutions on the air-sensitive compounds were carried out in an argon-filled glove box or in standard Schlenk flasks and Schlenk apparatuses. All solvents were dried and stored over molecular sieves. The commercially available metal salts and halogen compounds were used without further purification. The noncoordinating salts were dried if necessary and stored and also dispensed, if they are hygroscopic, in a glove box. The olefins and the internal standard were if necessary degassed and dried over molecular sieves. All ring-closing metathesis products and cross-metathesis products are known; they were determined quantitatively relative to hexadecane by means of gas chromatography.
Ruthenium compounds of the general formulae XII-XX were examined to determine their activity and selectivity in the ring-closing metathesis reaction of diethyl diallylmalonate to form diethyl cyclopent-3-ene-1,1-dicarboxylate relative to the cycloisomerization reaction. The results are summarized in Table 4.
A 250 ml three-neck flask was charged with 961.2 mg (4.00 mmol) of diethyl diallylmalonate, 452.6 mg (2.00 mmol) of hexadecane and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 25.5 mg (0.04 mmol) of the ruthenium compound XIV were dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In addition, the solvent was distilled off from the reaction mixture and the residue was fractionated by means of column chromatography to give 271.0 mg of diethyl cyclopent-3-ene-1,1-dicarboxylate (yield isolated: 32.0%).
A 250 ml three-neck flask was charged with 4.00 mmol of diethyl diallylmalonate, 2.00 mmol of hexadecane, 0 mmol-0.20 mmol of Lewis acid (AlCl3, PdCl2(PPh3)2, Fe(OAc)2 or Fe(acac)3), 0 mmol-0.20 mmol of NaPF6 and 100 ml of dry solvent (toluene or xylene) and the reaction mixture was heated to 80-140° C. in a stream of argon. In a glove box, 0.04 mmol of the ruthenium compound (XII-XVIII) was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at the desired reaction temperature for 1-3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). The specific reaction conditions and results are shown in Table 4.
A 250 ml three-neck flask was charged with 4.00 mmol of diethyl diallylmalonate, 2.00 mmol of hexadecane, 0.20 mmol of Fe(acac)3, 0.20 mmol of NaPF6, 0.04 mmol of 1,2-dibromocyclohexane and 100 ml of dry toluene and the reaction mixture was heated to 40-100° C. in a stream of argon. In a glove box, 0.04 mmol of the ruthenium compound XIV was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at the desired reaction temperature for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). The specific reaction conditions and results are shown in Table 4.
A 250 ml three-neck flask was charged with 4.00 mmol of diethyl diallylmalonate, 2.00 mmol of hexadecane, 0.20 mmol of Fe(acac)3, 0.20 mmol of NaPF6, 0.04 mmol of 1,2-dibromocyclohexane and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box 0.04 mmol of the ruthenium compound (XIX or XX) and 0.04 (1:1) or 0.08 (1:2) mmol of a corresponding imidazolium salt (VI*HCl or VII*HCl) were dissolved together with 0.04 mmol (1:1) or 0.08 mmol (1:2) of NaO-t-Bu in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at the desired reaction temperature for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). The specific reaction conditions and results are shown in Table 4.
[a]Reaction conditions: diethyl diallylmalonate (4 mmol), Ru compound (1 mol %), NaPF6 (5 mol %) and Lewis acid (5 mol %), solvent (100 ml), stream of argon;
[b]determined by GC using hexadecane as internal standard;
[c]NaPF6 (1 mol %);
[d]NaPF6 (10 mol %);
[e]1,2-dibromocyclohexane (1 mol %) added.
The model catalyst system consisting of XIV, NaPF6 and Fe(acac)3 was examined to determine its activity and selectivity as a function of the presence of selected halogen compounds (H1-H17).
A 50 ml three-neck flask was charged with 1.00 mmol of diethyl diallylmalonate, 0.50 mmol of hexadecane, 0.05 mmol of Fe(acac)3, 0.05 mmol of NaPF6, 0.01 mmol of halogen compound (H1 to H17) and 21 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.01 mmol of XIV was dissolved in 4 ml of dry toluene and introduced into the hot reaction solution in the 50 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). The specific reaction conditions and results are shown in Table 5.
[a]Reaction conditions: diethyl diallylmalonate (1 mmol), (p-cymene)Ru(Me2IMes)Cl2 (XIV) (1 mol %), NaPF6 (5 mol %), Fe(acac)3 (5 mol %), halogen compound (1 mol %), toluene (25 ml), stream of argon, 80° C., 3 h;
[b] determined by GC using hexadecane as internal standard.
A 250 ml three-neck flask was charged with 4.00 mmol of diethyl 2-(but-3-enyl)-2-(2-methylallyl)malonate, 2.00 mmol hexadecane, 0.2 mmol of Fe(acac)3, 0.2 mmol of NaPF6 and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.04 mmol of XIV was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 mmol of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6 and Fe(acac)3, a conversion of 50% and an RCM yield of 24% were achieved.
A 250 ml three-neck flask was charged with 4.00 mmol of N,N-diallyl-4-methylbenzenesulphonamide, 2.00 mmol of hexadecane, 0.2 mmol of Fe(acac)3, 0.2 mmol of NaPF6 and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.04 mmol of XIV was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6 and Fe(acac)3, a conversion of 14% and an RCM yield of 12% were achieved.
A 50 ml three-neck flask was charged with 1.00 mmol of 4-benzyloxy-octa-1,7-diene, 0.50 mmol of hexadecane, 0.05 mmol of Fe(acac)3, 0.05 mmol of NaPF6, 0.01 mmol of 1,2-dibromocyclohexane and 21 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.01 mmol of XIV was dissolved in 4 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6, Fe(acac)3 and 1,2-dibromocyclohexane, a conversion of 85% and an RCM yield of 41% were achieved.
A 50 ml three-neck flask was charged with 1.00 mmol of 4-benzyloxyhepta-1,7-diene, 0.50 mmol of hexadecane, 0.05 mmol of Fe(acac)3, 0.05 mmol of NaPF6, 0.01 mmol of 1,2-dibromocyclohexane and 21 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.01 mmol of XIV was dissolved in 4 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask.
The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6, Fe(acac)3 and 1,2-dibromocyclohexane, a conversion of 90% and an RCM yield of 81% were achieved.
A 50 ml three-neck flask was charged with 1.00 mmol of 4-benzyloxy-4-methylhepta-1,7-diene, 0.50 mmol of hexadecane, 0.05 mmol of Fe(acac)3, 0.05 mmol of NaPF6 and 21 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.01 mmol of XIV was dissolved in 4 ml of dry toluene and introduced into the hot reaction solution in the 50 ml flask. The reaction solution was stirred at the desired reaction temperature for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6 and Fe(acac)3, a conversion of 95% and an RCM yield of 94% were achieved.
A 250 ml three-neck flask was charged with 4.00 mmol of 1-allyl-2-(allyloxy)benzene, 2.00 mmol of hexadecane, 0.2 mmol of Fe(acac)3, 0.2 mmol of NaPF6 and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.04 mmol of XIV was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at the desired reaction temperature for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was introduced in a countercurrent of argon into a GC vial, dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of 1 mol % of XIV, NaPF6 and Fe(acac)3, a conversion of 94% and an RCM yield of 85% were achieved.
A 250 ml three-neck flask was charged with 4.00 mmol of 1-allyl-2-(allyloxy)benzene, 2.00 mmol of hexadecane, 0.02 mmol of Fe(acac)3, 0.02 mmol of NaPF6 and 100 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.004 mmol of XIV was dissolved in 8 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of 0.01 mol % of XIV, NaPF6 and Fe(acac)3, a conversion of 94% and an RCM yield of 81% were achieved.
A 250 ml three-neck flask was charged with 4.00 mmol of styrene, 2.00 mmol of hexadecane, 2.0 mmol of Fe(acac)3, 2.0 mmol of NaPF6 and 80 ml of dry toluene and the reaction mixture was heated to 80° C. in a stream of argon. In a glove box, 0.4 mmol of XIV was dissolved in 20 ml of dry toluene and introduced into the hot reaction solution in the 250 ml flask. The reaction solution was stirred at 80° C. for 3 hours in a stream of argon. After the reaction was complete, 0.1 ml of the reaction solution was dissolved in 1.5 ml of ethyl acetate and analysed by means of an HP 6890 gas chromatograph (GC). In the presence of XIV, NaPF6 and Fe(acac)3, a conversion of 23% and a CM yield of 13% were achieved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13158985.5 | Mar 2013 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/052765 | 2/13/2014 | WO | 00 |
