Hydrogenation of Dienals or Dienones Using Rhodium Complexes under Carbon Monoxide-Free Atmosphere

Abstract

The present invention relates to the field of catalytic hydrogenation, and more particularly to the use of base-free catalytic systems comprising specific rhodium complexes for the reduction of conjugated dienals or dienones to the corresponding deconjugated enals or enones.

Description

[Technical field]

[0001] The present invention relates to the field of catalytic hydrogenation, and more particularly to the use of base-free catalytic systems comprising specific rhodium complexes for the reduction of conjugated dienals or dienones to the corresponding deconjugated enals or enones.

[0002] Background technology Direct selective α-β hydrogenation of conjugated dienals (α,γ-dienals) or conjugated dienones (α,γ-dienones), i.e., direct selective α-β hydrogenation of specific C=C bonds, is a challenging goal. In fact, hydrogenation can occur at three different sites (two C=C and one C=O). Moreover, to make such a process attractive for industrial purposes, it is preferable to achieve hydrogenation with acceptable conversion and reasonable turnover (complex loading and reaction time).

[0003] Selective α-β reduction of conjugated dienals or conjugated dienones has rarely been reported in the literature. Selective α-β hydrogenation of conjugated dienals has been reported in WO2012150053, where selective hydrogenation was achieved using at least a base and a C 34 ~C 60 The hydrogenation is carried out in the presence of a catalytic system comprising at least one complex in the form of a rhodium complex containing a bidentate diphosphine ligand (L2). However, the hydrogenations described in this prior art document are always carried out in the presence of a base, which, under such conditions, causes the formation of polymers instead of the desired product, which is a disadvantage for certain substrates. Moreover, this prior art document is silent about the selective α-β hydrogenation of dienones.

[0004] Therefore, there remains a need for a base-free hydrogenation process that allows the selective α-β hydrogenation of α,γ-dienals or α,γ-dienones, and preferably under industrially applicable reaction conditions. Prior art documents have described the use of a suitable Rh precursor having at least one CO ligand and a C ligand having a natural bite-angle of 85°-130°. 34 ~C 60 There have been no reports of the use of specific catalytic systems comprising at least one Rh(I) complex, obtained by reaction with a bidentate diphosphine ligand (L2), for the reduction of conjugated dienals or conjugated dienones.

[0005] Description of the Invention In order to solve the above problems, the present invention provides a method for the hydrogenation of C6 to C6 by using H2 molecules. 20 A method for reducing a conjugated dienal or conjugated dienone to the corresponding deconjugated enal or deconjugated enone, comprising: 34 ~C 60 It relates to a process, characterized in that it is carried out in the presence of a catalytic system comprising at least one complex in the form of a rhodium complex comprising a bidentate diphosphine ligand (L2) and at least one CO ligand.

[0006] According to a particular embodiment of the present invention, the compound of formula (I) [ka] [Wherein, when separate, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom, an optionally substituted phenyl group, a C1-C8 alkyl group, a C2-C8 alkenyl group, a C3-C8 cycloalkyl group, or a C3-C8 cycloalkenyl group, 1 , R 2 , R 3 , R 4 and R 5provided that at least one of R 1 and R 2 or R 2 and R 3 or R 3 and R 4 when taken together, represent an optionally substituted C3-C4 alkanediyl or alkenediyl group; or R 1 and R 3 or R 2 and R 5 when taken together, represent an optionally substituted C2-C3 alkanediyl or alkenediyl group; or R 4 and R 5 when taken together, represent an optionally substituted C4-C5 alkanediyl or alkenediyl group; or R 6 and R 1 or R 6 and R 2 when taken together, represent an optionally substituted C2-C4 alkanediyl or alkenediyl group; or R 6 and R 5 When taken together, C2 to C are optionally substituted. 10 represents an alkanediyl group or an alkenediyl group] The conjugated dienal or conjugated dienone is represented by the formula (II) [ka] [In the formula, R 1 From R 6 has the same meaning as defined in formula (I). Deconjugated enal (R 6 is a hydrogen atom) or deconjugated enone (R 6 is not a hydrogen atom); The method comprises the steps of: preparing a suitable Rh precursor having at least one CO ligand and a C ligand having a characteristic inclusion angle of 85° to 130°; 34 ~C 60 It is carried out in the presence of a catalytic system comprising at least one Rh(I) complex obtained by reaction with a bidentate diphosphine ligand (L2).

[0007] The expression "intrinsic angle" is understood in the usual sense in the art, e.g. as defined in PWNM VAN LEEUWEN, PCJ KAMER, JNH Reek, P. Dierkes, Chem. Rev. 2000, 2741.

[0008] R 1 From R 6 The possible substituents of each are optionally one, two or three C1-C3 alkyl groups or one, two or three COOR 7 Group, OCOR 7 group, N(R 7 )2 units, CNOR 8 Group or R 7 one phenyl group, one cyclohexyl group, cyclopentyl group, cyclohexenyl group or cyclopentenyl group, substituted with R 8 is a hydrogen atom or R 7 is a group, R 7 The group represents a C1-C4 linear or branched alkyl or alkenyl group. In particular, R 1 From R 6 The possible substituents of are one phenyl group or one, two or three COOR 7 Group, OR 8 Group or R 7 A group, where R 7 and R 8 has the same meaning as defined above. According to any one of the embodiments of the present invention, the R 1 From R 6 Only one or two of the R 1 From R 5 One or two of may be optionally substituted.

[0009] The wavy line indicates that the double bond may be in the form of its E or Z isomer or a mixture thereof; for example, C6-C 20The conjugated dienal or conjugated dienone may be in the form of a composition of matter consisting of one or more compounds of formula (I) having the same chemical structure but differing in the configuration of the double bonds. In particular, compound (I) contains two double bonds, each of which may be Z, E or a mixture thereof, and compound (II) contains one double bond, each of which may be Z, E or a mixture thereof. Compounds of formula (I) and compounds of formula (II) may be in the form of a mixture consisting of E and Z isomers, and wherein said isomer E is at least 50% or even at least 75% of the total mixture (i.e., E / Z mixture is 75 / 25 to 100 / 0).

[0010] For reasons of clarity, "R 1 and R 2 ... taken together represent a C3-C4 alkanediyl or alkenediyl group" or similar designations have the usual meaning as understood by those skilled in the art, i.e., a divalent radical formed from an alkane or alkene by removal of two hydrogen atoms. In other words, R 1 and R 2 when taken together, form a C5-C6 cycloalkyl or cycloalkenyl group.

[0011] It is understood that said compound (II) may be in racemic or optically active form, depending on the nature of the substrate and the complex used.

[0012] An "alkenyl", "cycloalkenyl" or "alkenediyl" group is understood herein to have the meaning ordinary in the art, which is an unsaturated group where the unsaturation cannot be conjugated to a carbon-carbon double bond of a conjugated dienal or dienone.

[0013] The terms "alkyl" and "alkenyl" groups are understood to include both branched and straight chain alkyl and alkenyl groups.

[0014] "Conjugated dienal" is understood to mean a compound having at least two carbon-carbon double bonds and an aldehyde functional group, three of which are conjugated as shown in formula (I). The term "conjugated dienal" is therefore understood to also include compounds having additional non-aromatic carbon-carbon double bonds, provided that said additional carbon-carbon double bonds are not conjugated with the double bonds of the dienal system. "Conjugated dienone" is understood to mean a compound having at least two carbon-carbon double bonds and a ketone functional group, three of which are conjugated as shown in formula (I). The term "conjugated dienone" is therefore understood to also include compounds having additional non-aromatic carbon-carbon double bonds, provided that said additional carbon-carbon double bonds are not conjugated with the double bonds of the dienal system.

[0015] "Deconjugated enal" is understood to mean a compound having at least one γ-δ carbon-carbon double bond and an aldehyde function, as shown in formula (II). The term "deconjugated enal" is therefore understood to also include compounds having an additional carbon-carbon double bond, provided that said additional non-aromatic carbon-carbon double bond is not conjugated with the double bond of the enal system. "Deconjugated enone" is understood to mean a compound having at least one γ-δ carbon-carbon double bond and a ketone function, as shown in formula (II). The term "deconjugated enone" is therefore understood to also include compounds having an additional carbon-carbon double bond, provided that said additional non-aromatic carbon-carbon double bond is not conjugated with the double bond of the enone system.

[0016] According to any embodiment of the present invention, the compounds of formula (I) and (II) are C6-C 15 It is a compound.

[0017] According to any embodiment of the present invention, when separate, R 1 , R 2 , R 3 , R 4 , R5 and R 6 Each of R independently represents a hydrogen atom, an optionally substituted phenyl group, a C1-C6 alkyl group, a C5-C6 cycloalkyl group, or a C5-C6 cycloalkenyl group. 1 , R 2 , R 3 , R 4 and R 5 provided that at least one of R 3 and R 4 when taken together, represent an optionally substituted C3-C4 alkanediyl group; R 4 and R 5 when taken together, represent an optionally substituted C4-C5 alkanediyl group. In particular, when taken separately, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom, a phenyl group, a C1-C4 alkyl group, a C5-C6 cycloalkyl group, or a C5-C6 cycloalkenyl group, each of which is optionally substituted, 1 , R 2 , R 3 , R 4 and R 5 provided that at least one of R 3 and R 4 when taken together, represent an optionally substituted C3-C4 alkanediyl group; R 4 and R 5 when taken together represent an optionally substituted C4-C5 alkanediyl group.

[0018] According to any embodiment of the present invention, the compounds of formula (I) and (II) are conjugated dienones and deconjugated enones, respectively; i.e., R 6 may each optionally be a phenyl group, a C1 to C8 alkyl group, a C2 to C8 alkenyl group, a C3 to C8 cycloalkyl group, or a C3 to C8 cycloalkenyl group.

[0019] According to any one of the above embodiments, when separate, said R 1 may represent a hydrogen atom or a C1-C4 alkyl group. In particular, R 1 may represent a hydrogen atom or a C1-C3 alkyl group. 1 may represent a hydrogen atom, a methyl group or an ethyl group. 1 may represent a hydrogen atom.

[0020] According to any one of the above embodiments, when separate, said R 6 may represent a hydrogen atom, a C1-C4 alkyl group or a phenyl group. In particular, R 6 may represent a hydrogen atom, a C1-C3 alkyl group or a phenyl group. 6 may represent a hydrogen atom, a methyl group, an ethyl group or a phenyl group. 6 may be a methyl or ethyl group.

[0021] According to any one of the above embodiments, when separate, said R 2 may represent a hydrogen atom or a C1-C4 alkyl group. In particular, R 2 may represent a hydrogen atom or a C1-C3 alkyl group. 2 may represent a hydrogen atom, a methyl group or an ethyl group. 2 may represent a hydrogen atom.

[0022] According to any one of the above embodiments, when separate, said R 3 may represent a hydrogen atom, an optionally substituted C1-C4 alkyl group or a phenyl group. In particular, R 3 may represent a hydrogen atom, a C1-C3 alkyl group or a phenyl group. 3 may represent a hydrogen atom, a methyl or ethyl group, or an optionally substituted phenyl group.

[0023] According to any one of the above embodiments, when separate, said R 4may represent a hydrogen atom, a methyl group, an ethyl group, a cyclohexyl group, a cyclohexenyl group, a cyclopentyl group, a cyclopentenyl group, or a phenyl group, each of which may be optionally substituted.

[0024] According to any one of the above embodiments, when separate, said R 5 may represent a hydrogen atom, a methyl group, an ethyl group, a cyclohexyl group, a cyclohexenyl group, a cyclopentyl group, a cyclopentenyl group, or a phenyl group, each of which may be optionally substituted.

[0025] According to any one of the above embodiments, when taken together, said R 3 and R 4 when taken together represent an optionally substituted C4 alkanediyl group.

[0026] According to any one of the above embodiments, when taken together, said R 4 and R 5 when taken together represent an optionally substituted C5 alkanediyl group.

[0027] According to any one of the above embodiments, the substrate of formula (I) is R 1 , R 2 represent hydrogen atoms, and R 3 , R 4 , R 5 Each of R represents a hydrogen atom, a methyl group, an ethyl group, a cyclohexyl group, or a phenyl group, and the cyclohexyl group or the phenyl group may be optionally substituted. 1 , R 2 , R 3 , R 4 and R 5 provided that at least one of R 3 and R 4when taken together may represent an optionally substituted C4 alkanediyl group.

[0028] According to any one of the above embodiments, the substrate of formula (I) is 1 , R 2 , R 3 , R 4 and R 5 At least one or two of the may be a hydrogen atom.

[0029] According to any one of the above embodiments, the substrate of formula (I) is 1 , R 2 , R 3 , R 4 and R 5 Two or three of the may be hydrogen atoms.

[0030] According to any one of the above embodiments, the R 1 From R 6 The substitutions are one phenyl group or one, two or three OR 8 Group or R 7 group, where R 8 is a hydrogen atom or R 7 is a group, R 7 represents a C1-C4 linear or branched alkyl group. Preferably, the substitution is OR 7 Group or R 7 According to any one of the above embodiments of the present invention, said R 1 From R 5 Only one or two of R may be optionally substituted. 7 may represent a C1-C3 alkyl group. 7 may represent a methyl or ethyl group.

[0031] According to a further embodiment of the present invention, the substrate may be a conjugated dienal or a conjugated dienone that provides a deconjugated enal or a deconjugated enone that may be useful as an end product or an intermediate product in the pharmaceutical, agrochemical or flavoring industry.A particularly preferred substrate may be a conjugated dienal or a conjugated dienone that provides a deconjugated enal or a deconjugated enone that may be useful as an end product or an intermediate product in the flavoring industry.

[0032] Non-limiting examples of substrates are: (3E,5E)-5-methyl-6-(p-tolyl)hexa-3,5-dien-2-one, (3E,5Z)-5-phenylhepta-3,5-dien-2-one, (3E)-5-methylocta-3,5-dien-2-one, (3E)-5-ethylnona-3,5-dien-2-one, (3E)-5-propyldeca-3,5-dien-2-one, (3E,5E)-6-cyclopentyl-5-methylhexa-3,5-dien-2-one, (3E,5E)-6-cyclohexyl-5-methylhexa-3,5-dien-2-one, (3E,5E)-5-(cyclohexylmethylene)hept-3-en-2-one, (E)-4-(5,5-dimethylcyclohex-1-en-1-yl)but-3-en-2-one, (E)-4-(2,6,6-trimethylcyclohex-1-en-1-yl)but-3-en-2-one, (3E,5E)-6-(cyclohex-3-en-1-yl)-5-methylhexa-3,5-dien-2-one, (3E,5E)-5-methyl-7-(2,6,6-trimethylcyclohex-1-en-1-yl)hepta-3,5-dien-2-one, (3E,5E) -5-ethyl-7-((S)-2,2,3-trimethylcyclopent-3-en-1-yl)hepta-3,5-dien-2-one, 6-cyclohexylhepta-3,5-dien-2-one, 6,10-dimethylundeca-3,5,9-trien-2-one, (3E,5E)-6-phenylhexa-3,5-dien-2-one, (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal, (2E,4E)-5-phenylpenta-2,4-dienal, (2E,4E)-5-phenylhexa-2,4-dienal, (2E,4E)-4-methyl ethyl-5-phenylpenta-2,4-dienal, (2E,4E)-2-methyl-5-phenylpenta-2,4-dienal, (2E,4Z)-4-phenylhexa-2,4-dienal, (E)-3-(4-(tert-butyl)cyclohex-1-en-1-yl)acrylaldehyde, (2E,4E)-5-cyclohexyl-4-methylpenta-2,4-dienal, (2E,4E)-5,9-dimethyldeca-2,4,8-trienal, 5,9-dimethyldeca-2,4-dienal, (2E,4E)-5-cyclopentyl-4-methylpenta-2,4-dienal, 5-methyl-7-phenylhepta-2,4-dienal, (E)-3-(5,5-dimethylcyclohex-1-en-1-yl)acrylaldehyde or (2E)-4-methyldodeca-2,4-dienal.

[0033] According to a particular aspect of any one of the embodiments of the present invention, the process of the present invention is also characterized in that it provides compound (II) with a selectivity of more than 40%, in particular more than 60%, in particular more than 80%, in particular more than 90% and more particularly more than 95%.

[0034] According to a particular aspect of any one of the embodiments of the present invention, the process of the present invention is also characterized in that it provides compound (II) with a conversion rate from the starting compound of more than 60%, in particular more than 70%, in particular more than 80%, in particular more than 90% and more particularly more than 95%.

[0035] Here, "deconjugated enal" refers to compound (II), "aldehyde" refers to compound (I) in which both carbon-carbon double bonds have been reduced, "alcohol" refers to an aldehyde in which the carbonyl has also been reduced, and here, "deconjugated enone" refers to compound (II) and "ketone" refers to compound (I) in which both carbon-carbon double bonds have been reduced.

[0036] The hydrogenation reaction can be carried out in the presence or absence of a solvent. In certain embodiments of the invention, the process is carried out in the presence of a solvent (generally for practical reasons), and any solvent that is widely accepted in hydrogenation reactions can be used for the purposes of the invention. Non-limiting examples include C6-C 10These include aromatic solvents such as toluene or xylene, C1-C2 halogenated hydrocarbons such as CH2Cl2, C5-C8 hydrocarbon solvents such as hexane or cyclohexane, C4-C9 ethers such as tetrahydrofuran or MTBE, C3-C9 esters such as ethyl acetate or methyl acetate, C3-C6 ketones such as acetone, polar solvents such as C1-C5 primary or secondary alcohols such as isopropanol or ethanol, or mixtures thereof. The solvent is chosen depending on the nature of the substrate and the complex, and the skilled person is well able to choose the most convenient solvent in each case to optimize the hydrogenation reaction.

[0037] In the hydrogenation method of the present invention, the reaction can be carried out under a pure H2 atmosphere or under a mixture of hydrogen and at least an inert gas, such as N2 or Ar. Preferably, the atmosphere of the reaction medium is CO-free, e.g., the amount of CO present is less than 1 ppm. In any case, it is understood that the reaction medium is preferably provided with at least a stoichiometric amount of H2 compared to the substrate; it is understood that if there is less than a stoichiometric amount of H2, only partial conversion of the substrate is achieved. In any case, as a non-limiting example, a typical H2 pressure is 10 5 Pa~80×10 5 The pressure may be between 1 and 80 bar, or higher if desired. Again, the skilled artisan can easily adjust the pressure depending on the amount of complex added and the dilution of the substrate in the solvent. By way of example, typical pressures are between 3 and 50×10 5 Pa (3-50 bar), or even 5-20×10 5 Pa (5 to 20 bar).

[0038] The temperature at which the hydrogenation can be carried out ranges from 20° C. to 100° C., preferably from 25° C. to 80° C. Of course, the skilled person can also select the preferred temperature depending on the melting and boiling points of the starting and final products and the desired reaction or conversion time.

[0039] According to any embodiment of the present invention, the process of the present invention is carried out in the absence of a base.

[0040] As mentioned above, the present invention relates to a method for preparing a Rh(I) precursor having at least one CO ligand and a C ligand having a specific intercalation angle of 85° to 130°. 34 ~C 60 It involves the use of a specific catalytic system comprising at least one Rh(I) complex obtained by reaction with a bidentate diphosphine ligand (L2).

[0041] According to any one of the above embodiments, the Rh(I) complex is: - C with inherent clamping angle of 85°~130° 34 ~C 60 With bidentate diphosphine ligand (L2); - Formula (1) or Formula (1') [ka] [In the formula, p is an integer of 1 to 4; q is an integer of 2 to 20; r is an integer of 0 to 1; Z is a coordination anion, and P is a C3 to C 30 monophosphine] with a suitable Rh precursor This is the compound obtained by reacting these together.

[0042] According to any one of the above embodiments, Z may be a coordinating anion, provided that Z is not a halide. In particular, Z may be selected from the group consisting of acetylacetonate, 1,1,1,5,5,5-hexafluoropentane-2,4-dionate, 2,2,6,6-tetramethylheptane-3,5-dionate, carboxylates such as benzoate, acetate, formate, pivalate or propionate, alkoxides such as methoxide, ethoxide, propoxide or butoxide, allyls such as prop-2-en-1-ide, 3-phenyl-prop-2-en-1-ide, cyclopentadienyl, pentamethylcyclopentadienyl and pentafluorocyclopentadienyl. In particular, Z may be acetylacetonate.

[0043] According to any embodiment of the present invention, P has the formula PR 9 3, where R 9 is optionally substituted, C1 to C 12 R is a group, for example a linear, branched or cyclic alkyl, alkoxy or aryloxy group, or a substituted or unsubstituted phenyl, diphenyl or naphthyl or di-naphthyl group. 9 may represent a substituted or unsubstituted phenyl, diphenyl or naphthyl or di-naphthyl group. b Possible substituents of the radicals are those listed below: Preferably, P is triphenylphosphine.

[0044] According to any embodiment of the present invention, the Rh(0) precursor of formula (1) or formula (1′) is selected from the group consisting of Rh(CO)2(acac), RhH(CO)(PPh3)3, Rh4(CO) 12 and Rh(CO) 16 may be selected from the group consisting of:

[0045] The preparation of the Rh(I) complex is preferably carried out in the presence of a solvent. In a particular embodiment of the invention, said solvent is the same as that optionally used in the hydrogenation process. However, other solvents can also be used, non-limiting examples being C6-C 10 Examples of suitable solvents include aromatic solvents such as toluene or xylene, C5-C8 hydrocarbon solvents such as hexene or cyclohexane, C4-C9 ethers such as tetrahydrofuran or MTBE, polar solvents such as C1-C5 primary or secondary alcohols such as isopropanol or ethanol, dichloromethane, water or mixtures thereof. The solvent is chosen depending on the nature of the substrate and the complex, and the skilled person is well able to select the most convenient solvent in each case to optimize the hydrogenation reaction.

[0046] The preparation of Rh(I) complexes can be carried out under an inert atmosphere, or under an atmosphere that is essentially carbon monoxide and oxygen free, for example, under an atmosphere in which the amount of CO and O2 present is less than 1 ppm. Those skilled in the art know what is meant by an inert atmosphere. Non-limiting examples of such atmospheres are nitrogen or argon atmospheres.

[0047] In the preparation of Rh(I) complexes, the process temperature can be comprised between 0° C. and 100° C., preferably between 10° C. and 60° C. Of course, the skilled person can also select the preferred temperature depending on the melting and boiling points of the starting and final products and the desired reaction or conversion times.

[0048] According to a particular embodiment, the Rh(I) complex has the formula (2) [ka] wherein L2 and Z have the same meanings as defined above. It is believed that the present invention can be described as having the following structure:

[0049] According to any one of the above embodiments, L2 is a group represented by the formula (A): [ka] [In the formula, each R b are each an optionally substituted C6 to C 10 Represents an aromatic group or an optionally substituted cyclohexyl group, or two R b taken together represent an optionally substituted 2,2'-oxydiphenyl group. and Q is an optionally substituted C 10 ~C 16 A metallocenediyl group or a) Formula (i) [ka] [In the formula, each R d represents a hydrogen atom or a C1-C8 alkyl group, and X represents an oxygen atom, a sulfur atom, or a C(R 10 )2 units, Si(R 11 )2 or NR 10 A group, where R 10 is a hydrogen atom or R 11 is a group, R 11 represents a C1-C4 linear or branched alkyl group, preferably a methyl group. or - b) Formula (ii) [ka] [In the formula, m is 0 or 1, M represents Fe or Ru, and R a represents a hydrogen atom or a C1-C4 alkyl group] represents a group represented by the formula: The wavy line indicates the location of the bond between the Q group and the remainder of compound (A).

[0050] According to any one of the above embodiments, Q is optionally substituted 1,1'-ferrocenediyl or a) Formula (i') [ka] [In the formula, each R d represents a hydrogen atom or a C1-C4 alkyl group, and X is C(R 10 )2 units, Si(R 11 )2 or NR 10 represents a group, where R 10 is a hydrogen atom or R 11 is a group, R 11 represents a C1-C4 linear or branched alkyl group, preferably a methyl group. or - b) Formula (ii') [ka] represents a group in any enantiomeric form; The wavy line indicates the location of the bond between the Q group and the remainder of compound (A).

[0051] According to any one of the above embodiments, in the definition of Q, the metallocene diyl group is a ferrocenediyl group and in particular a 1,1'-diyl group. In particular, in formula (ii), M is Fe.

[0052] According to any one of the above embodiments, each R b is an optionally substituted C6-C 10 It represents an aromatic group or an optionally substituted cyclohexyl group.

[0053] According to any one of the above embodiments, "aromatic group or ring" means a phenyl group or a naphthyl group, and in particular a phenyl group.

[0054] According to any one of the above embodiments, each R b represents a phenyl group, a cyclohexyl group, a 3,5-dimethylphenyl group, a 3,5-di(CF3)-phenyl group, or a 3,5-dimethyl-4-methoxy-phenyl group.

[0055] According to any one of the above embodiments, R d represents a hydrogen atom.

[0056] According to any one of the above embodiments, X represents a CMe2, SiMe2, NH or NMe group.

[0057] According to any one of the above embodiments, L2 has a characteristic included angle of between 93° and 125°, in particular between 97° and 125°, in particular between 102° and 125°, in particular between 108° and 125°, and even more particularly between 110° and 125°.

[0058] According to any one of the above embodiments, the non-limiting R b Examples of possible substituents are halogen atoms or C1-C 10 The substituents are one, two, three or four groups selected from among an alkoxy group, an alkyl group, an alkenyl group, or a perhalohydrocarbon group. For example, the expression "perhalohydrocarbon" has the meaning usual in the art, such as a group CF3, as used herein. In particular, the substituents are one or two halogen atoms (e.g. F or Cl) or a C1-C4 alkoxy or alkyl group, or a CF3 group.

[0059] According to any one of the above embodiments, non-limiting examples of possible substituents of the metallocenediyl group or the 1,1′-ferrocenediyl group include one or two C1-C4 alkyl groups or CR d’ PhN(R d’’ ) groups, where R d’ or R d’’ is a hydrogen atom or a C1-C4 alkyl group, Ph is a phenyl group, R b may be optionally substituted as indicated above for In particular, said substituents are one methyl group or one CH(C6H5)N(Me)2 group.

[0060] According to any one of the above embodiments, the R b The groups, metallocenediyl groups or 1,1'-ferrocenediyl groups, either one by one or all together, are unsubstituted.

[0061] According to any one of the above embodiments, the ligand of formula (A) may be in racemic or optically active form.

[0062] Non-limiting examples of L2 ligands include: [ka] [In the formula, Cy represents a cyclohexyl group substituted with one or two C1-C4 alkyl groups, and Ph represents a phenyl group optionally substituted with one or two C1-C4 alkyl groups, one or two trifluoromethyl groups, or one methoxy group] Where applicable, said compounds are in optically active form or racemic.

[0063] The ligands (A) are all known in the prior art and can be obtained by the skilled person by application of standard general methods well known in the prior art (see for example RPJ Bronger, PCJ Kamer, PWNM van Leeuwen, Organometallics 2003, 22, 5358 or RPJ Bronger, JP Bermon, J. Herwig, PCJ Kamer, PWNM van Leeuwen, Adv. Synth. Catal. 2004, 346, 789 or M. Kranenburg, YEM van der Burgt, PCJ Kamer, PWNM van Leeuwen, K. Goubitz, J. Fraanje Organometallics 1985, 14, 3081 or P. Dierkes, PWNM van Leeuwen J. Chem. Soc., Dalton Trans. 1999, 1519). Some of the ligands are even commercially available.

[0064] According to any one of the above embodiments, the L2 ligand is selected from the group consisting of (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) and 4,6-bis(diphenylphosphanyl)-10H-phenoxazine.

[0065] Generally, complexes of formula (2) can be prepared and isolated prior to their use in the processes according to common methods described in the literature, which are described in the Examples.

[0066] Furthermore, the complexes can be prepared in situ, by several methods, in the hydrogenation medium, without isolation or purification, immediately prior to use.

[0067] The Rh complex of the present invention can be added to the reaction medium of the method of the present invention in a wide range of concentrations.As a non-limiting example, the amount of complex compared to the amount of substrate can be more than 10 ppm, preferably more than 100 ppm, more preferably more than 1000 ppm, but less than 50000 ppm, more preferably less than 10000 ppm.Needless to say, the optimal concentration of the complex will depend on the nature of the complex, the substrate, the nature of the solvent and the pressure of H2 used in the method, as well as the desired reaction time, as known to those skilled in the art.

[0068] Working Example The invention will now be described in more detail by way of the following examples, in which the abbreviations have their usual meaning in the art and temperatures are given in degrees Celsius (°C). NMR spectra were obtained using a Bruker Avance II Ultrashield 400 plus (400 MHz ( 1 H) and 100MHz ( 13 C) or Bruker Avance III 500 (500MHz ( 1 H) and 125MHz ( 13 C) or Bruker Avance III 600 cryoprobe (600MHz ( 1 H) and 150MHz (13 C) and spectra were internally referenced to tetramethylsilane at 0.0 ppm. 1 H NMR signal shifts are expressed in δ ppm and coupling constants (J) are expressed in Hz with the following multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; b, broad (indicating unresolved couplings) and were analyzed using Bruker Topspin software. 13 C NMR data are reported in terms of chemical shifts δ ppm and hybridization states measured by the DEPT90 and DEPT135 methods, where C is quaternary (s); CH is methine (d); CH2 is methylene (t); and CH3 is methyl (q).

[0069] Example 1 Catalytic hydrogenation of dienones A typical experimental procedure is as follows: In a glove box under argon, a solution of Rh(CO)2(acac) and Nixantphos (L2, structure shown in table) in dichloromethane was stirred for 30 min. The dienone solution in ethanol was placed in a 75 mL autoclave, followed by a solution of [Rh(Nixantphos)(CO)(acac)] (0.1 or 0.2 mol %) in dichloromethane. The autoclave was closed, purged with hydrogen gas (10 x 20 bar), and pressurized with hydrogen gas at 20 bar or 50 bar depending on the reaction conditions. The autoclave was placed in an oil bath set at 60 °C and reacted with magnetic stirring for an appropriate time. At the end of the reaction, the autoclave was cooled in an ice bath and depressurized. The reaction mixture was concentrated under reduced pressure. The crude product was then purified by bulb to bulb distillation to give the desired ketone (shown separately).

[0070] Hydrogenation of (E)-5-methyl-6-p-tolylhex-5-en-2-one The autoclave was charged successively with (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (4.081 g, 19.97 mmol) in ethanol (18 mL) and a solution of [Rh(Nixantphos)(CO)(acac)] in dichloromethane (2 mL) prepared from Rh(CO)2(acac) (5.0 mg, 0.02 mmol) and Nixantphos (11.6 mg, 0.02 mmol). The reaction mixture was heated under H2 pressure (20 bar) for 2 h 30 min. Purification by bulb-to-bulb distillation (bp = 157 °C, under 1.2 mbar) gave (E)-5-methyl-6-p-tolylhex-5-en-2-one (3.858 g, 18.69 mmol, 94% yield) as a pale yellow oil (GC purity = 98%).

number

[0071] Example 2 Catalytic hydrogenation of the dienone of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one using various RhX(Ln) complexes General procedure for screening various rhodium complexes with diphosphine Ln: In a glove box, glass vials equipped with magnetic stir bars were separately charged with solutions of diphosphine (Ln, structure shown in Table 1) (1 mol%) and rhodium precatalyst (1 mol%) in toluene. After stirring at room temperature for 1 hour, a solution of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1, structure shown in Table 7) (0.5 mmol / vial) in toluene (1 mL, 0.5 M, 0.5 mmol) was added. The vials were placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 5 bar. The reaction was allowed to stir at room temperature for 20 hours. The autoclave was then vented and samples were removed from each vial and analyzed by GC. The results are shown in Table 2. [Table 1-1] [Table 1-2] [Table 1-3] [Table 2] Items 1 and 2 are comparative examples. Complex / base = molar ratio to substrate (ppm). Conv. = conversion of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one)] / [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one) + sum of other products]. *Potassium acetate was added to the reaction mixture (10 mol %). **Dichloromethane was used in place of toluene in this example. *** The reaction stopped after 4 hours.

[0072] Example 3 Catalytic hydrogenation of the dienone of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1) using various Rh(COD)Cl(Ln) complexes - Comparative example (conditions reported in WO2012150053) General procedure for screening various diphosphines (Ln) with [Rh(COD)Cl]2: In a glove box, glass vials equipped with magnetic stir bars were separately charged with the appropriate diphosphine (Ln) (1 mol%) shown in Table 1, [Rh(COD)Cl]2 (0.5 mol%), potassium acetate (10 mol%) and toluene (1 mL). After stirring for 1 h at room temperature, a solution of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1, structure shown in Table 7) in toluene (1 mL, 0.5 M, 0.5 mmol) was added. The vials were placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar and finally pressurized with hydrogen gas at 5 bar. The reaction was allowed to stir at room temperature for 20 h. The autoclave was then vented and samples were removed from each vial and analyzed by GC. The results are shown in Table 3. [Table 3] Complex / base = molar ratio to substrate (ppm). Conv. = conversion of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one)] / [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one) + sum of other products].

[0073] Example 4 Catalytic hydrogenation of the dienone of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1) using various Rh(Ln)(CO)(acac) complexes General procedure for screening rhodium complexes with various diphosphines L1-L4: In a glove box, glass vials equipped with magnetic stir bars were separately charged with the appropriate diphosphine (L1-L4) (1 mol%) shown in Table 1 and a solution (1 mL) of Rh(CO)2(acac) (1 mol%) in toluene. After stirring at room temperature for 1 hour, a solution of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1 shown in Table 7) (0.5 M, 0.5 mmol) in toluene was added. The vials were placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 5 bar. The reaction was allowed to stir at room temperature for 20 hours. The autoclave was then vented and samples were removed from each vial and analyzed by GC. The results are shown in Table 4. [Table 4] Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one)] / [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one) + sum of other products].

[0074] Example 5 Catalytic hydrogenation of the dienone of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1) using various Rh(L1-L2)(CO)(acac) complexes in various solvents General procedure for screening Rh(L1-L2)(CO)(acac) in various solvents: In a glove box, a glass vial equipped with a magnetic stir bar was charged with the appropriate preformed Rh(L1-L2)(CO)(acac) complex (0.5 mol%) followed by (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (1 mmol, S1 shown in Table 7) and the appropriate solvent (2 mL). The vial was placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 5 bar. The reaction was allowed to stir at 60 °C for 4 hours. The autoclave was then cooled in an ice / water bath and degassed. Samples were removed from the vials and analyzed by GC. The results are shown in Table 5. [Table 5] Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one)] / [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one) + sum of other products].

[0075] Example 6 Catalytic hydrogenation of the dienone of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1) using Rh(L2)(CO)(acac) complex at various pressures and temperatures General procedure for screening Rh(L2)(CO)(acac) at various pressures and temperatures: In a glove box, a stainless steel autoclave equipped with a magnetic stir bar was charged with the preformed Rh(L2)(CO)(acac) complex (0.1 mol%), followed by (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (5 mmol, S1 shown in Table 7) and EtOH (10 mL). The autoclave was closed and purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at the indicated pressure and allowed to react with stirring at the desired temperature for the indicated time. The autoclave was then cooled in an ice / water bath and vented. Samples were removed from the vials and analyzed by GC. The results are shown in Table 6. [Table 6] Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one)] / [((E)-5-methyl-6-(p-tolyl)hex-5-en-2-one) + sum of other products].

[0076] Example 7 Catalytic hydrogenation of various dienones (S1-S15) using the Rh(L2)(CO)(acac) complex: General procedure for hydrogenation of dienones using Rh(L2)(CO)(acac): In a glove box, a stainless steel autoclave equipped with a magnetic stir bar was charged with CH2C l2The preformed Rh(L2)(CO)(acac) complex (0.1 mol %) in 2 mL of ethyl acetate was charged, followed by the appropriate dienone (20 mmol) as shown in Table 7 and EtOH (18 mL). The autoclave was closed, purged with hydrogen gas at 20 bar and finally pressurized with hydrogen gas at 20 bar and the reaction stirred at 60° C. for the times shown. The autoclave was then cooled in an ice / water bath and vented. The products were isolated by evaporation of the solvent under reduced pressure and purified by column chromatography on silica gel. The results are shown in Table 8. [Table 7-1] [Table 7-2] [Table 8] Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S1-17 to the desired product gamma-delta-unsaturated ketone and to any other products (including fully saturated aromatic ketones) after the indicated time ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 x [desired gamma-delta-unsaturated ketone] / [desired gamma-delta-unsaturated ketone + sum of other products]. Yield = yield of isolation after purification. ND=Undecided. *The reaction was carried out under 50 bar hydrogen pressure. **Hydrogenation of both the 3,4- and 9,10-positioned C=C bonds (15%) was observed along with the desired product (71%) and some unknown isomers of the fully hydrogenated product (7%).

[0077] Example 8 Catalytic hydrogenation of (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) using various RhX(L1) complexes: General procedure for screening various rhodium complexes with diphosphine L1: In a glove box, a glass vial equipped with a magnetic stir bar was charged with Xantphos (L1, structure shown in Table 1) (1 mol%), rhodium precatalyst (1 mol%) and CHC l2 (1 mL) was added separately. After stirring at room temperature for 1 hour, l2 A solution of (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) (structure shown in Table 7) in was added (1 mL, 1 M, 1 mmol). The vials were placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 50 bar. The reaction was allowed to stir for 1 hour at room temperature. The autoclave was then vented and samples were removed from each vial and analyzed by GC. [Table 9] Items 1 to 4 are comparative examples. Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S18 to the desired aldehyde (E)-4-methyl-5-(p-tolyl)pent-4-enal and any other products (including the saturated alcohol (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol) after 1 hour in this example ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [(E)-4-methyl-5-(p-tolyl)pent-4-enal] / [(E)-4-methyl-5-(p-tolyl)pent-4-enal + (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol].

[0078] Example 9 Catalytic hydrogenation of (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) using various Rh(CO)(acac)(Ln) complexes: General procedure for screening various diphosphines: In a glove box, a glass vial equipped with a magnetic stir bar was charged with the appropriate diphosphine (Ln) (1 mol, as shown in Table 1), Rh(CO)2(acac) (1 mol %), and CH2C 12 (1 mL) was added separately. After stirring at room temperature for 1 hour, l2 A solution of (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) in water (1 mL, 0.5 M, 0.5 mmol) was added. The vials were placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 50 bar. The reaction was allowed to stir for 1 hour at room temperature. The autoclave was then vented and samples were taken from each vial and analyzed by GC. The results are shown in Table 10. [Table 10] Complex / base = molar ratio to substrate (ppm). Conv. = Conversion of S18 to the desired aldehyde (E)-4-methyl-5-(p-tolyl)pent-4-enal and any other products (including the saturated alcohol (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol) after 1 hour in this example ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [(E)-4-methyl-5-(p-tolyl)pent-4-enal] / [(E)-4-methyl-5-(p-tolyl)pent-4-enal + (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol].

[0079] Example 10 Catalytic hydrogenation of (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) using Rh(CO)(acac)(L1) complex in various solvents: General procedure for screening Rh(L1)(CO)(acac) in various solvents: In a glove box, a glass vial equipped with a magnetic stir bar was charged with the preformed Rh(L1)(CO)(acac) complex (0.1 mol%), followed by (2E,4E)-4-methyl-5-(p-tolyl)penta-2,4-dienal (S18) (5 mmol, shown in Table 7) and the appropriate solvent (5 mL). The vial was placed in a 75 mL autoclave. The autoclave was closed, purged with hydrogen gas at 20 bar, and finally pressurized with hydrogen gas at 50 bar. The reaction was then allowed to stir for 1 hour at room temperature. The autoclave was then vented. Samples were removed from the vial and analyzed by GC. The results are shown in Table 11. [Table 11] Conv. = Conversion of S18 to the desired aldehyde (E)-4-methyl-5-(p-tolyl)pent-4-enal and any other products (including the saturated alcohol (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol) after 1 hour in this example ((%), analyzed by GC). Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [(E)-4-methyl-5-(p-tolyl)pent-4-enal] / [(E)-4-methyl-5-(p-tolyl)pent-4-enal + (E)-4-methyl-5-(p-tolyl)pent-4-en-1-ol].

[0080] Example 11 Catalytic hydrogenation of (3E,5E)-5-methyl-6-p-tolylhexa-3,5-dien-2-one (S1) using Rh(COD)(acac) or Rh(CO)2(acac) complexes - Comparative Example: The general procedure reported in Example 1 was followed and L2 was used, and the results are shown in Table 12. [Table 12] Items 2 and 3 are comparative examples. Conv. = Conversion ((%), analyzed by GC) of S1 to the desired product (E)-5-methyl-6-(p-tolyl)hex-5-en-2-one and to any other products, including the fully saturated aromatic ketone 5-methyl-6-(p-tolyl)hexan-2-one and the deconjugated enone 5-methyl-6-(p-tolyl)hex-4-en-2-one (mixture of E and Z isomers), after as indicated. Sel. = selectivity ((%), analyzed by GC), calculated as 100 × [(E)-5-methyl-6-(p-tolyl)hex-5-en-2-one] / [(E)-5-methyl-6-(p-tolyl)hex-5-en-2-one + sum of other products].

Claims

1. H ２ Using a molecule of formula (I) 【Chemistry 1】 [wherein, when separate, R １ , R ２ , R ３ , R ４ , R ５ and R ６ each independently represents a hydrogen atom, an optionally substituted phenyl group, C １ ~C ８ Alkyl group, C ２ ~C ８ Alkenyl group, C ３ ~C ８ Cycloalkyl group, or C ３ ~C ８ represents a cycloalkenyl group, １ , R ２ , R ３ , R ４ and R ５ provided that at least one of R １ and R ２ Or R ２ and R ３ Or R ３ and R ４ When taken together, they are optionally substituted C ３ ~C ４ represents an alkanediyl group or an alkenediyl group; or R １ and R ３ Or R ２ and R ５ When taken together, they are optionally substituted C ２ ~C ３ represents an alkanediyl group or an alkenediyl group; or R ４ and R ５ When taken together, they are optionally substituted C ４ ~C ５ represents an alkanediyl group or an alkenediyl group; or R ６ and R １ Or R ６ and R ２ When taken together, they are optionally substituted C ２ ~C ４ represents an alkanediyl group or an alkenediyl group; or R ６ and R ５ When taken together, they are optionally substituted C ２ ~C １０ represents an alkanediyl group or an alkenediyl group] C ６ ~C ２０ A conjugated dienal or conjugated dienone is reacted with a compound represented by formula (II) 【Chemistry 2】 [In the formula, R １ From R ６ has the same meaning as defined in formula (I). R ６ When R is a hydrogen atom, it is a deconjugated enal or R ６ is not a hydrogen atom, to a deconjugated enone; A suitable Rh precursor having at least one CO ligand and a C ligand having a characteristic inclusion angle of 85° to 130°. ３４ ~C ６０ The process is carried out in the presence of a catalytic system comprising at least one Rh(I) complex obtained by reaction with a bidentate diphosphine ligand (L2).

2. The compounds of formula (I) and formula (II) are represented by the formula １ , R ２ , R ３ , R ４ , R ５ and R ６ each independently represents a hydrogen atom, an optionally substituted phenyl group, C １ ~C ４ Alkyl group, C ５ ~C ６ Cycloalkyl group or C ５ ~C ６ represents a cycloalkenyl group, １ , R ２ , R ３ , R ４ and R ５ provided that at least one of R ３ and R ４ When taken together, they are optionally substituted C ３ ~C ４ R represents an alkanediyl group; ４ and R ５ When taken together, they are optionally substituted C ４ ~C ５ C represents an alkanediyl group ６ ~C １５ The method of claim 1 , wherein the compound is a compound.

3. The compounds of formula (I) and formula (II) are represented by the formula: １ , R ２ each independently represents a hydrogen atom; R ３ represents a hydrogen atom, a methyl group, an ethyl group, or an optionally substituted phenyl group; R ４ , R ５ each independently represents a hydrogen atom, a methyl group, an ethyl group, a cyclohexyl group, a cyclohexenyl group, a cyclopentyl group, a cyclopentenyl group, or a phenyl group, and the cyclohexyl group, the cyclohexenyl group, the cyclopentyl group, the cyclopentenyl group, or the phenyl group is each optionally substituted, １ , R ２ , R ３ , R ４ and R ５ provided that at least one of R ３ and R ４ When taken together, they are optionally substituted C ４ 3. The method of claim 1 or 2, wherein the compound represents an alkanediyl group.

4. 3. The process according to claim 1 or 2, which is carried out in the absence of a base.

5. The Rh precursor is RhH(CO)(PPh ３ ) ３ , Rh(CO) ２ (acac), Rh ４ (CO) １２ and Rh ６ (CO) １６ The method of claim 1 or 2, wherein the compound is selected from the group consisting of:

6. The Rh(I) complex is represented by the formula (2): 【Chemistry 3】 [wherein L2 has the same meaning as in claim 1, and Z is a coordinating anion] The method of claim 1 or 2, wherein the compound is

7. L2 is a group represented by the formula (A) 【Chemistry 4】 [In the formula, when they are different, each R ｂ is an optionally substituted C ６ ~C １０ represents an aromatic group or an optionally substituted cyclohexyl group, or, when taken together, two R ｂ represents an optionally substituted 2,2'-oxydiphenyl group. is a compound of the formula: and Q is an optionally substituted C １０ ~C １６ represents a metallocenediyl group, or a) a compound of formula (i) 【Chemistry 5】 [In the formula, each R ｄ is a hydrogen atom or C １ ~C ８ represents an alkyl group, and X is an oxygen atom, a sulfur atom, or a C(R １０ ) ２ group, Si(R １１ ) ２ Group or NR １０ group, where R １０ is a hydrogen atom or R １１ group, R １１ is C １ ~C ４ represents a linear or branched alkyl group, preferably a methyl group. Based on; or - b) Formula (ii) 【Chemistry 6】 [In the formula, m is 0 or 1, M represents Fe or Ru, and R ａ is a hydrogen atom or C １ ~C ４ represents an alkyl group; represents a group of the wavy line indicates the location of the bond between the Q group and the remainder of compound (A); and R ｂ The substitution is a halogen atom or C １ ~C １０ one, two, three or four groups selected from an alkoxy group, an alkyl group, an alkenyl group, or a perhalohydrocarbon group; Possible substituents of the metallocene diyl group are one or two C １ ~C ４ Alkyl group, or CR ｄ’ PhN(R ｄ’’ ) ２ group, where R ｄ’ Or R ｄ’’ is a hydrogen atom or C １ ~C ４ is an alkyl group, Ph is a phenyl group, and R ｂ may be optionally substituted as indicated above for 3. The method according to claim 1 or 2.

8. The R ｂ each represents an optionally substituted C ６ ~C １０ 8. The method of claim 7, wherein R represents an aromatic group or an optionally substituted cyclohexyl group.

9. Q is optionally substituted 1,1'-ferrocenediyl or a) a compound of formula (i') 【Chemistry 7】 [In the formula, each R ｄ is a hydrogen atom or C １ ~C ４ represents an alkyl group, and X is C(R １０ ) ２ group, Si(R １１ ) ２ Group or NR １０ represents a group, where R １０ is a hydrogen atom or R １１ group, R １１ is C １ ~C ４ represents a linear or branched alkyl group, preferably a methyl group. or - b) Formula (ii) 【Chemistry 8】 represents a group in any one of the enantiomeric forms of The method of claim 7, wherein the wavy line indicates the location of the bond between the Q group and the remainder of compound (A).

10. The method according to claim 7, wherein L2 has a characteristic included angle between 93° and 125°, preferably between 97° and 120°.

11. 8. The method of claim 7, wherein L2 is selected from the group consisting of (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) and 4,6-bis(diphenylphosphanyl)-10H-phenoxazine.

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