Process for the selective catalytic hydrogenation of dienones

Abstract

The present disclosure provides a catalyst system capable of selectively hydrogenating (2,3) / (4,5) and (2,3) / (5,6) dienones with hydrogen gas. Specifically, the present disclosure provides a catalyst capable of providing high selectivity for the reduction even in the absence of pyridine, pyrazine, quinoline, and quinoxaline.

Description

[Technical field]

[0001] The present invention provides a method for selective hydrogenation of (2,3) / (4,5) unsaturated dienones using rhodium or ruthenium complexes without the need for nitrogen-containing additives such as pyridine, pyrazine, quinoline, and quinoxaline. [Background technology]

[0002] Technical pseudoionones (PIs) are one of the intermediates to vitamin A and are therefore readily available from vitamin A manufacturers (see Tetrahedron 2016, 72, 1645-1652). Direct hydrogenation allows the production of the valuable intermediate geranylacetone-type PI. Geranylacetone is typically produced as an E / Z-mixture from linalool as described in H. Surburg and J. Panten, Common Fragrance and Flavor Materials, 4th Ed., Wiley-VCH, Weinheim 2016. Technical PIs are produced and used as mixtures of possible stereoisomers in any ratio, namely 3E / 5E-PI, 3E / 5Z-PI, 3Z / 5E-PI and 3Z / 5Z-PI. The 3E / 5E-PI isomer is the major isomer of technical PIs. Geranylacetone from PI by hydrogenation is produced as an E / Z-mixture, as shown in Scheme 1 below. [ka]

[0003] Although processes for the selective monohydrogenation of (2,3) / (4,5)-unsaturated dienones to the corresponding (4,5)-unsaturated enones are known in the literature, few methods have been reported that can operate with the efficiency required for use in the chemical industry.

[0004] The hydrogenation of β-ionone to the corresponding dihydrogen ion has been described using heterogeneous copper catalysis under hydrogen atmosphere at 1 bar and 90 °C (Journal of Molecular Catalysis 74, 1992, 267-74). A similar process is described in Catalysts 2020, 10, 515, where the hydrogenation of β-ionone is carried out at 1 bar of hydrogen and 90 °C. Despite these reports, the direct hydrogenation of pseudoionone (PI) to geranylacetone (GAC) using homogeneous catalysts has only been reported recently.

[0005] Pseudoionone (PI) is more difficult to handle as a substrate for selective monohydrogenation at the (2,3) position compared to β-ionone because β-ionone is tetrasubstituted at the second double bond, whereas pseudoionone (PI) is trisubstituted (the difference in the substrate-dependent reactivity of the two double bonds in each molecule is greater for β-ionone than for pseudoionone, making selective monohydrogenation of pseudoionone more difficult). Journal of Molecular Catalysis 74, 1992, 267-74 further describes that for certain substrates such as β-ionone, the second double bond in the molecule isomerizes, resulting in a lower yield in selective monohydrogenation. Therefore, heterogeneous catalysts cannot be used for the hydrogenation of pseudoionone (PI) to geranylacetone (GAC) because they may cause further double bond isomerization.

[0006] The rhodium-catalyzed selective reduction of (2,3) / (4,5)-unsaturated dienones such as β-ionone to the corresponding dihydroions with Et3SiH has been reported in Organometallics 10, 1982, 1390-1399. However, Et3SiH is less atom-efficient than hydrogen.

[0007] Chinese Patent No. 105218339 describes the conditions for selective hydrogenation of methylheptyldienone to methylheptanone using Pd(acac)2 / 1,2-bis(diphenylphosphino)ethane or Rh(PPh3)3Cl / 1,2-bis(diphenylphosphino)ethane as catalyst.

[0008] WO 2012 / 150053 reports a homogeneous rhodium catalyst system for the selective hydrogenation of (2,3) / (4,5) unsaturated aldehydes to the corresponding (4,5) unsaturated aldehydes. The patent does not describe the application of such a catalyst system to the selective hydrogenation of (2,3) / (4,5) unsaturated dienones.

[0009] China Patent Publication No. 201811560479.9 describes a method for selective hydrogenation of (2,3) / (4,5) unsaturated dienones using Ru complexes in the presence of catalyst poison. It is noted that the hydrogenation of pseudoionone (PI) to geranylacetone (GAC) with hydrogen proceeds with high selectivity only in the presence of nitrogen-containing additives such as pyridine, pyrazine, quinoline, and quinoxaline.

[0010] The reduction of (2,3) / (4,5) unsaturated esters has been reported in Angew Chem. Int. Ed., 2019, 58, 12246-51 using a Rh catalyst with formic acid as the reducing agent as opposed to hydrogen. However, formic acid is less atom-efficient than hydrogen. In the published case, Z-(3,4) unsaturated esters are obtained.

[0011] Thus, no system has been described so far that catalyzes the hydrogenation of pseudoionone (PI) to geranylacetone (GAC) with high selectivity using hydrogen gas in the absence of pyridine, pyrazine, quinoline, and quinoxaline. The present inventors have surprisingly found a catalytic system that can hydrogenate PI in the absence of catalyst poisons while retaining high selectivity. Summary of the Invention [Means for solving the problem]

[0012] The present disclosure provides a method for selective hydrogenation of a dienone. Specifically, the present disclosure provides a method comprising: 1) combining a dienone with one or more solvents; 2) adding a catalyst to the mixture of the dienone and the solvent to obtain a reaction mixture; and 3) mixing the reaction mixture under an atmosphere comprising hydrogen (H2). The atmosphere may also further comprise carbon monoxide (CO). The catalyst may comprise one or more transition metals, such as, for example, rhodium and ruthenium. The catalyst may further comprise one or more ligands, such as, for example, mono- or bis-phosphines. The reaction may be carried out in the absence of catalyst poisons, such as pyridine, pyrazine, quinoline, or quinoxaline, while still retaining high selectivity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1.Definition In the definitions of the variables shown above and in the formulae below, generic names are generally used to represent the respective substituents. n -~C m The designation - indicates the respective possible number of carbon atoms in the particular substituent or substituent moiety.

[0014] In the context of the present invention, the expression "alkyl" includes unbranched or branched alkyl groups having 1 to 4, 6, 12 or 25 carbon atoms. These include, for example, C1-C6-alkyl, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 2-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, etc.

[0015] In the context of the present invention, the expression "cycloalkyl" refers to a cyclic saturated hydrocarbon group having 3 to 6, 12 or 25 carbon ring members, for example C3-C8-cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, or C7-C 12 - Including bicycloalkyl.

[0016] In the context of the present invention, the expression "alkoxy" means an alkyl group having 1 to 6 carbon atoms attached via oxygen, for example C1-C6-alkoxy, such as methoxy, ethoxy, n-propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy, 2-methylpropoxy, 1,1-dimethylethoxy, pentoxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 1,1-dimethylpropoxy, 1,2-dimethylpropoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, 2-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 2 ... methoxy, hexoxy, 1-methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1,1-dimethylbutoxy, 1,2-dimethylbutoxy, 1,3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1-ethyl-1-methylpropoxy, or 1-ethyl-2-methylpropoxy.

[0017] In the context of the present invention, the expression "alkenyl" includes unbranched or branched hydrocarbon groups having 2 to 4, 6, 12 or 25 carbon atoms, containing at least one double bond, for example 1, 2, 3 or 4 double bonds. These include, for example, C2-C6-alkenyl, such as ethenyl, 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-methyl-1-butenyl, 2-methyl-1-butenyl, 3-methyl-1-but ... Methyl-2-butenyl, 2-methyl-2-butenyl, 3-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-ethyl-1-propenyl, 1-ethyl-2-propenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 2 -methyl-1-pentenyl, 3-methyl-1-pentenyl, 4-methyl-1-pentenyl, 1-methyl-2-pentenyl, 2-methyl-2-pentenyl, 3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1-methyl-3-pentenyl, 2-methyl-3-pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl, 1-methyl-4-pentenyl, 2-methyl-4-pentenyl, 3-methyl-4-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl, 1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1,3-dimethyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 3,3-dimethyl-1-butenyl, 3,Examples of the aryl group include 3-dimethyl-2-butenyl, 1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-trimethyl-2-propenyl, 1-ethyl-1-methyl-2-propenyl, 1-ethyl-2-methyl-1-propenyl, and 1-ethyl-2-methyl-2-propenyl.

[0018] In the context of the present invention, the expression "alkylene" refers to a divalent hydrocarbon radical having 2 to 25 carbon atoms. The divalent hydrocarbon radical may be unbranched or branched. These include, for example, C2-C 16 - alkylene radicals, for example 1,4-butylene, 1,5-pentylene, 2-methyl-1,4-butylene, 1,6-hexylene, 2-methyl-1,5-pentylene, 3-methyl-1,5-pentylene, 1,7-heptylene, 2-methyl-1,6-hexylene, 3-methyl-1,6-hexylene, 2-ethyl-1.5-pentylene, 3-ethyl-1,5-pentylene, 2,3-dimethyl-1,5-pentylene, 2,4-dimethyl-1,5-pentylene, 1,8-octylene, 2-methyl-1,7-heptylene, 3-methyl-1,7-heptylene, 4-methyl-1,7-heptylene, 2-ethyl-1,6-hexylene, 3-ethyl-1,6-hexylene, 2,3-dimethyl-1,6-hexylene , 2,4-dimethyl-1,6-hexylene, 1,9-nonylene, 2-methyl-1,8-octylene, 3-methyl-1,8-octylene, 4-methyl-1,8-octylene, 2-ethyl-1,7-heptylene, 3-ethyl-1,7-heptylene, 1,10-decylene, 2-methyl-1,9-nonylene, 3-methyl-1,9-nonylene, 4-methyl -1,9-nonylene, 5-methyl-1,9-nonylene, 1,11-undecylene, 2-methyl-1,10-decylene, 3-methyl-1,10-decylene, 5-methyl-1,10-decylene, 1,12-dodecylene, 1,13-tridecylene, 1,14-tetradecylene, 1,15-pentadecylene, and 1,16-hexadecylene.

[0019] In a mono- or poly-branched or substituted alkylene group, the carbon atoms at the branch points or at each branch point or bearing substituents can, independently of one another, have the R-configuration or the S-configuration, or both configurations in equal or differing proportions.

[0020] In the context of the present invention, the expression "alkenylene" refers to a divalent hydrocarbon group having 2 to 25 carbon atoms, which may be unbranched or branched, and whose main chain has one or more double bonds, for example 1, 2 or 3 double bonds. These include, for example, C2-C 18-Alkenylene groups, for example, ethylene, propylene, 1- and 2-butylene, 1- and 2-pentylene, 1-, 2- and 3-hexylene, 1,3-hexadienylene, 1,4-hexadienylene, 1-, 2- and 3-heptylene, 1,3-heptadienylene, 1,4-heptadienylene, 2,4-heptadienylene, 1-, 2- and 3-octenylene, 1,3-octadienylene, 1,4-octadienylene, 2,4-octadienylene, 1-, 2- and 3-nonenylene 1-, 2-, 3-, 4-, 5-decenylene, 1-, 2-, 3-, 4-, 5-undecenylene, 2-, 3-, 4-, 5-, 6-dodecenylene, 2,4-dodecadienylene, 2,5-dodecadienylene, 2,6-dodecadienylene, 3-, 4-, 5-, 6-tridecenylene, 2,5-tridecadienylene, 4,7-tridecadienylene, 5,8-tridecadienylene, 4-, 5-, 6-, 7-tetradecenylene, 2,5-tetradecadienylene, 4,7-tetradecadienylene, tetradecadienylene, 5,8-tetradecadienylene, 4-, 5-, 6-, 7-pentadecenylene, 2,5-pentadecadienylene, 4,7-pentadecadienylene, 5,8-pentadecadienylene, 1,4,7-pentadecatrienylene, 4,7,11-pentadecatrienylene, 4,6,8-pentadecatrienylene, 4-, 5-, 6-, 7-, 8-hexadecenylene, 2,5-hexadecadienylene, 4,7-hexadecadienylene, 5,8-hexadeca Examples of the alkyl group include sadecadienylene, 2,5,8-hexadecatrienylene, 4,8,11-hexadecatrienylene, 5,7,9-hexadecatrienylene, 5-, 6-, 7-, and 8-heptadecenylene, 2,5-heptadecadienylene, 4,7-heptadecadienylene, 5,8-heptadecadienylene, 5-, 6-, 7-, 8-, and 9-octadecadienylene, 2,5-octadecadienylene, 4,7-octadecadienylene, and 5,8-octadecadienylene.

[0021] The double bonds of the alkenylene radicals can be present independently of one another in the E configuration as well as in the Z configuration or as a mixture of both configurations.

[0022] In connection with the present invention, the expression "halogen" includes fluorine, chlorine, bromine and iodine, preferably fluorine, chlorine or bromine.

[0023] In the context of the present invention, the term "aryl" refers to mononuclear to trinuclear aromatic ring systems containing 6 to 14 carbon ring members. These include, for example, C6 to C 10 -aryl, for example phenyl or naphthyl.

[0024] In the context of the present invention, the expression "hetaryl" includes mononuclear to trinuclear aromatic ring systems containing 6 to 14 carbon ring members, in which one or more, for example 1, 2, 3, 4, 5 or 6 carbon atoms are replaced by nitrogen, oxygen and / or sulfur atoms. These include, for example, C3 to C9-hetaryl groups, such as 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-pyrrolyl, 3-pyrrolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4-imidazolyl, 1,2,4-oxadiazol-3-yl, 1,2,4-oxadiazol-5-yl, 1,2,4-thiazolyl ... Examples of the indolyl include diazolyl-3-yl, 1,2,4-thiadiazol-5-yl, 1,2,4-triazol-3-yl, 1,3,4-oxadiazol-2-yl, 1,3,4-thiadiazol-2-yl, 1,3,4-triazol-2-yl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 2-pyrazinyl, 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, and 7-indolyl.

[0025] In the context of the present invention, the expression "aralkyl" includes mono- or binuclear aromatic ring systems containing 6 to 10 carbon ring members, which are linked via unbranched or branched C1-C6-alkyl groups. These include, for example, C7-C 12 -aralkyl, for example, phenylmethyl, 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl, 2-phenylpropyl, 3-phenylpropyl, and the like.

[0026] In the context of the present invention, the expression "aralkyl" includes mono- or binuclear aromatic ring systems containing 6 to 10 carbon ring members, which are substituted with one or more, for example 1, 2 or 3, unbranched or branched C1-C6-alkyl groups. These include, for example, C7-C 12-alkylaryl, such as 1-methylphenyl, 2-methylphenyl, 3-methylphenyl, 1-ethylphenyl, 2-ethylphenyl, 3-ethylphenyl, 1-propylphenyl, 2-propylphenyl, 3-propylphenyl, 1-isopropylphenyl, 2-isopropylphenyl, 3-isopropylphenyl, 1-butylphenyl, 2-butylphenyl, 3-butylphenyl, 1-isobutylphenyl, 2-isobutylphenyl, 3-isobutylphenyl, 1-sec-butylphenyl, 2-sec-butylphenyl, 3-sec-butylphenyl, 1-tert-butylphenyl, 2-tert-butylphenyl, 3-tert-butylphenyl, 1-(1-pentenyl)phenyl, 2-(1-pentenyl)phenyl, 3-(1-pentenyl)phenyl, 1-(2-pentenyl)phenyl, 2-(2-pentenyl)phenyl phenyl, 3-(2-pentenyl)phenyl, 1-(3-pentenyl)phenyl, 2-(3-pentenyl)phenyl, 3-(3-pentenyl)phenyl, 1-(1-(2-methylbutyl))phenyl, 2-(1-(2-methylbutyl))phenyl, 3-(1-(2-methylbutyl))phenyl, 1-(2-(2-methylbutyl))phenyl, 2-(2-(2-methylbutyl))phenyl, 3-(2-(2-methylbutyl))phenyl phenyl, 1-(3-(2-methylbutyl))phenyl, 2-(3-(2-methylbutyl))phenyl, 3-(3-(2-methylbutyl))phenyl, 1-(4-(2-methylbutyl))phenyl, 2-(4-(2-methylbutyl))phenyl, 3-(4-(2-methylbutyl))phenyl, 1-(1-(2,2-dimethylpropyl))phenyl, 2-(1-(2,2-dimethylpropyl))phenyl, 3-(1-(2,2-dimethylpropyl))phenyl, 1-(1-hexenyl)phenyl, 2-(1-hexenyl)phenyl, 3-(1-hexenyl)phenyl, 1-(2-hexenyl)phenyl, 2-(2-hexenyl)phenyl, 3-(2-hexenyl)phenyl, 1-(3-hexenyl)phenyl, 2-(3-hexenyl)phenyl, 3-(3-hexenyl)phenyl, 1-(1-(2-methylpentenyl))phenyl, 2-(1-(2-methylpentenyl))phenyl, 3-(1-(2-methylpentenyl))phenyl, 1-(2-(2-methylpentenyl))phenyl, 2-(2-(2-methylpentenyl))phenyl, 3-(2-(2-methylpentenyl))phenyl, 1-(3-(2-methylpentenyl))phenyl, 2-(3-(2-methylpentenyl))phenyl, 3-(3-(2-methylpentenyl))phenyl, 1 -(4-(2-methylpentenyl))phenyl, 2-(4-(2-methylpentenyl))phenyl, 3-(4-(2-methylpentenyl))phenyl, 1-(5-(2-methylpentenyl))phenyl, 2-(5-(2-methylpentenyl))phenyl, 3-(5-(2-methylpentenyl))phenyl, 1-(1-(2,2-dimethylbutenyl))phenyl, 2-(1-(2,2-dimethylbutenyl))phenyl phenyl, 3-(1-(2,2-dimethylbutenyl))phenyl, 1-(3-(2,2-dimethylbutenyl))phenyl, 2-(3-(2,2-dimethylbutenyl))phenyl, 3-(3-(2,2-dimethylbutenyl))phenyl, 1-(4-(2,2-dimethylbutenyl))phenyl, 2-(4-(2,2-dimethylbutenyl))phenyl, 3-(4-(2,2-dimethylbutenyl))phenyl, and the like.

[0027] 2. Catalyst The present disclosure provides a catalytic system that can selectively hydrogenate dienones using hydrogen gas. Suitable dienones can include, for example, (2,3) / (4,5) and (2,3) / (5,6) dienones, such as pseudoionone, β-ionone, 6-methyl-3,5-heptadien-2-one, and α-ionone. Specifically, the present disclosure provides a catalyst that can provide high selectivity for reduction. Surprisingly, it has been found that the catalytic system of the present disclosure can catalyze hydrogenation under hydrogen gas in the absence of catalyst poisons such as pyridine, pyrazine, quinoline, and quinoxaline while achieving high selectivity. This would be particularly desirable since these catalyst poisons must be removed after the reaction. Thus, the method of the present disclosure allows for high selectivity, higher atomic efficiency, and simpler purification.

[0028] The catalyst may be composed of one or more transition metals and one or more ligands.

[0029] The one or more transition metals may be selected from the group including ruthenium, rhodium, platinum, palladium, and nickel.

[0030] The catalyst can be formed by reacting a transition metal-containing precursor with a ligand (and optionally additional reagents such as H2, CO, MeOH, reducing agents, etc.) in any ratio to form a metal-ligand complex. For example, when the ligand is a neutral bidentate bisphosphine ligand, the metal-ligand complex can be one of the following forms: (L)M(CO)X; (L)M(CO)2X; (L)M(CO)XY; (L)M(CO)XYZ. For example, when the ligand is a monodentate phosphine ligand, the metal-ligand complex can be one of the following forms: (L)2M(CO)X; (L)2M(CO)2X; (L)3M(CO)X; (L)2M(CO)XY; (L)2M(CO)XY; (L)2M(CO)XYZ. X, Y and Z are each independently an anionic monodentate ligand, such as H, Cl, Br, OAc, OH, acac, OMe, OEt, or OAlkyl. Suitable metal-containing precursors include Rh(CO)2acac, Rh(III) acetate, or [Ru(COD)(2-methylallyl)2].

[0031] Other suitable metal-containing precursors include rhodium or ruthenium metal complexes.Suitable rhodium compounds are particularly those that are soluble in the selected reaction medium, such as rhodium(0), rhodium(I), rhodium(II) oxide and rhodium(III) oxide, such as rhodium(III) chloride, rhodium(III) bromide, rhodium(III) nitrate, rhodium(III) sulfate, rhodium(II) oxide or rhodium(III) oxide, rhodium(II) acetate or rhodium(III) acetate, rhodium(II) carboxylate or rhodium(III) carboxylate, Rh(acac)3, [Rh(cod)Cl]2, [Rh(cod)2]BF4, Rh2(OAc)4, bis(ethylene)rhodium(I)acac, Rh(CO)2acac, [Rh(cod)OH]2, [Rh(cod)OMe]2, Rh4(CO) 12 , or Rh6(CO) 16 where "acac" is the acetylacetonate ligand, "cod" is the cyclooctadiene ligand, and "OAc" is the acetate ligand.

[0032] Further catalytic rhodium compounds may include carbonyl-containing rhodium compounds of the type LRh(CO)H (L=monodentate phosphine), LRh(CO)H (L=monodentate phosphine), or LRh(CO)H (L=bidentate phosphine), or LRh(CO)H (L=bidentate phosphine). Such complexes have been used for olefin hydrogenation, as described by Wilkinson et al. in J. Chem. Soc. (A) 1968, 2665-2671 (with (PPh3)3Rh(CO)H) or by Brei et al. in Tetrahedron Letters 2005, 6171-6179 (with (PPh3)3Rh(CO)H), or by Delongchamps et al. in Can. J. Chem 1990, 2137-2143, or by Jaekel et al. in Adv. Synth. Catal. 2008, 2708-2714 (with (Chiraphos)Rh(CO)2H), but not for the selective hydrogenation of unsaturated dienones. Such carbonyl compounds can be used as isolated complexes or prepared by preforming the catalyst.

[0033] Suitable ruthenium compounds are in particular those which are soluble in the selected reaction medium, such as ruthenium(0), ruthenium(I), ruthenium(II) and ruthenium(III) salts, e.g. [Ru(p-cymene)Cl2]2, [Ru(CO)4(ethylene)], [Ru(COD)(OAc)2], [Ru(CO)2Cl2]. n , [Ru(CO)3Cl2]2, [RuCl3*H2O], [Ru(acetylacetonate)3], [Ru(benzene)Cl2] n , [Ru(COD)(2-methylallyl)2], [Ru(DMSO)4Cl2], [Ru(PPh3)3(CO)(H)Cl], [Ru(PPh3)3(CO)Cl2], [Ru(PPh3)3(CO)(H)2], [Ru(PPh3)3Cl2], [Ru(COD)Cl2]2, [Ru(pentamethylcyclopentadienyl)(COD)Cl], [Ru3(CO 12 ] etc.

[0034] The ligand may comprise one or more bisphosphines, one or more monophosphines, or a combination thereof. The ligand may be 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), bis[(2-diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane) (SPANPhos), triphenylphosphite (P(OPh)3), 6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-[1,1'-biphenyl]-2,2'-diyl)bis(oxy)]bis(6H-dibenzo[d,f][1,3,2]dioxaphosphepine) (BiPhePhos), trimethylphosphite (P(OMe)3), triethylphosphite (P(OEt)3), The ligand may be selected from the group including (3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine (MonoPhos), (R,R)Chiraphos, (S,S)Chiraphos, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), triphenylphosphine (PPh3), tris(4-methoxyphenyl)phosphane, tris(3,5-bis(trifluoromethyl)phenyl)phosphane, 1,1'-bis(diisopropylphosphino)ferrocene (dippf), and methyldiphenylphosphane. The structure of the ligand is shown below. "Me" is methyl, "Ph" is phenyl, "Cy" is cyclohexyl, i Pr is understood to mean isopropanol. [ka]

[0035] The transition metal complex may be present in the reaction in an amount of about 0.01 mol% or more, about 0.05 mol% or more, about 0.1 mol% or more, about 0.2 mol% or more, about 0.3 mol% or more, about 0.4 mol% or less, about 0.5 mol% or less, about 0.6 mol% or less, about 0.7 mol% or less, about 0.8 mol%, about 0.9 mol% or less, about 1.0 mol% or less, or any value encompassed by these endpoints.

[0036] The molar ratio of ligand (which may be a monodentate or bidentate phosphine ligand) to metal may be about 0.9:1 or more, about 1.0:1 or more, about 1.5:1 or more, about 2.0:1 or more, about 2.5:1 or more, about 3.0:1 or more, about 5:1 or more, about 10:1 or more, about 20:1 or more, about 30:1 or more, about 40:1 or more, about 50:1 or less, about 60:1 or less, about 70:1 or less, about 80:1 or less, about 90:1 or less, about 100:1 or less, or any value encompassed by these endpoints. In chemical processes, the ligand may be oxidized or partially oxidized over time, for example, by oxidative contamination in the feed. Also, the catalyst may be decomposed by base or thermal stress over time. Thus, the optimal ratio of ligand to metal depends on various parameters and may be different for different setups.

[0037] The ligand may be present in the reaction in an amount of about 0.01 mol% or more, about 0.05 mol% or more, about 0.1 mol% or more, about 0.5 mol% or more, about 1.0 mol% or more, about 2.0 mol% or more, about 3.0 mol% or more, about 4.0 mol% or less, about 5.0 mol% or less, about 6.0 mol% or less, about 7.0 mol% or less, about 8.0 mol% or less, about 9.0 mol% or less, about 10.0 mol% or less, or any value encompassed by these endpoints.

[0038] The reaction may be carried out in the presence of a base such as Na2CO3, NaOMe, NaOEt, or trialkylamines such as triethylamine, ethyldiisopropylamine, and triisopropylamine.

[0039] 3.Reaction conditions As described above, the catalyst can provide high selectivity for the reduction of (2,3) / (4,5) and (2,3) / (5,6) dienones even in the absence of pyridine, pyrazine, quinolone, and quinoxaline. Suitable dienones can include, for example, (2,3) / (4,5) and (2,3) / (5,6) dienones, such as pseudoionone, β-ionone, 6-methyl-2-hept-5-en-2-one, and α-ionone.

[0040] In one embodiment, suitable substrates for the reaction include (2,3) / (4,5) dienones of formula I, as shown below: [ka] In the formula, R 1 is C1-C6 alkyl, C1-C6 alkoxy, or R 2 and R 2 is hydrogen, C1-C6 alkyl, or R 1 and R 3 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 4 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 5 and R 5 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 4 and a bond forming an optionally substituted 5- or 6-membered ring.

[0041] In another embodiment, suitable substrates for the reaction can include a (2,3) / (5,6) dienone of formula II shown below. [ka] In the formula, R 6is C1-C6 alkyl or C1-C6 alkoxy; R 7 is hydrogen or C1-C6 alkyl; R 8 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 9 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 10 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 11 and R 11 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 10 and a bond forming an optionally substituted 5- or 6-membered ring.

[0042] To carry out the reaction, the transition metal complex and the ligand can be combined in one or more solvents under an inert atmosphere to obtain the active catalyst. The inert atmosphere can be composed of, for example, nitrogen (N2) gas or argon (Ar) gas.

[0043] The molar ratio of transition metal complex to ligand can be 1:1 or more, 1:1.05 or more, 1:1.10 or more, 1:1.20 or more, 1:1.30 or more, 1:1.40 or less, 1:1.50 or less, 1:1.60 or less, 1:1.70 or less, 1:1.80 or less, 1:1.90 or less, 1:2.00 or less, 1:2.10 or less, 1:2.20 or less, 1:2.50 or less, 1:3 or less, 1:4 or less, 1:5 or less, or any value encompassed by these endpoints.

[0044] Suitable solvents include, for example, methanol, ethanol, isopropanol, hexanol, texanol, tetrahydrofuran (THF), toluene, xylene, dioxane, n-butanol, ethyl acetate, dichloromethane (DCM), or diethyl ether (Et2O), or combinations thereof.

[0045] The transition metal complex and ligand may be stirred under an inert atmosphere for a period of about 10 minutes or more, about 20 minutes or more, about 30 minutes or more, about 40 minutes or more, about 50 minutes or more, about 60 minutes or less, about 70 minutes or less, about 80 minutes or less, about 90 minutes or less, or any value encompassed by these endpoints.

[0046] The transition metal complexes and ligands may be preformed by mixing the Rh-precursor and the ligands in one or more solvents under an inert atmosphere or under an atmosphere of hydrogen or carbon monoxide or a mixture of hydrogen and carbon monoxide in any ratio, at pressures ranging from 1 bar to 100 bar, as described, for example, in WO 2006 / 40096.

[0047] The transition metal complex and ligand may be combined at a temperature of about 20° C. or higher, about 30° C. or higher, about 40° C. or higher, about 50° C. or lower, about 60° C. or lower, about 70° C. or lower, about 80° C. or lower, or any value encompassed by these endpoints.

[0048] The active catalyst may then be combined with a solution containing the (2,3) / (4,5) dienone, which may further contain an additional solvent, such as methanol, ethanol, isopropanol, 1-hexanol, 1-decanol, 1-nonanol, texanol (3-hydroxy-2,2,4-trimethylpentyl isobutyrate), tetrahydrofuran (THF), toluene, ethyl acetate, dichloromethane (DCM), MTBE, or diethyl ether (EtO).

[0049] The solution may further include one or more co-solvents, such as alkylbenzenes. Suitable alkylbenzenes include, for example, toluene, ethylbenzene, xylene, mesitylene, and durene. Further suitable co-solvents include, for example, methanol, ethanol, isopropanol, 1-hexanol, 1-decanol, 1-nonanol, texanol (3-hydroxy-2,2,4-trimethylpentyl isobutyrate), tetrahydrofuran (THF), dioxane, n-butanol, ethyl acetate, or diethyl ether (Et2O). Co-solvents are most preferably used in an amount of about 5 wt% or more, about 10 wt% or more, about 15 wt% or more, about 20 wt% or more, about 25 wt% or more, about 30 wt% or more, about 40 wt% or more, about 45 wt% or less, about 50 wt% or less, about 55 wt% or less, about 60 wt% or less, about 65 wt% or less, about 70 wt% or less, about 75 wt% or less, about 80 wt% or less, or any value encompassed by these endpoints, as a percentage of the complete reaction mass.

[0050] The amount of (2,3) / (4,5) dienone in the reaction can be about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, about 35% or more, about 40% or more, about 45% or more, about 50% or less, about 55% or less, about 60% or less, about 65% or less, about 70% or less, about 75% or less, about 80% or less, about 85% or less, about 90% or less, about 95% or less, about 99% or less, about 99.9% or less, or any value encompassed by these endpoints. Preferably, the concentration is from about 10% to about 80% as a percentage of the total reaction mixture.

[0051] After adding the active catalyst to the (2,3) / (4,5) dienone solution, the nitrogen (N2) can be replaced with hydrogen (H2) by introducing pressures of 1-100 bar. The pressure is then carefully released and the process is repeated two more times.

[0052] The reaction can be carried out under a hydrogen (H2) atmosphere. The pressure of the hydrogen atmosphere can be about 1 bar or more, about 5 bar or more, about 10 bar or more, about 20 bar or more, about 30 bar or more, about 40 bar or more, about 50 bar or less, about 60 bar or less, about 70 bar or less, about 80 bar or less, about 90 bar or less, about 100 bar or less, or any value inclusive of these endpoints.

[0053] The hydrogen atmosphere may further include carbon monoxide (CO), which may be present in an amount of about 1 ppm or more, about 5 ppm or more, about 10 ppm or more, about 50 ppm or more, about 100 ppm or more, about 200 ppm or more, about 500 ppm or more, about 700 ppm or more, about 1000 ppm or less, about 1200 ppm or less, about 1500 ppm or less, about 1700 ppm or less, about 2000 ppm or less, or any value encompassed by these endpoints.

[0054] The reaction can be carried out at a temperature of about 10°C to about 100°C, for example, 10°C or higher, 20°C or higher, about 30°C or higher, about 40°C or higher, about 50°C or higher, about 60°C or lower, about 70°C or lower, about 80°C or lower, about 90°C or lower, or any value encompassed by these endpoints.

[0055] The reaction can be stirred for about 1 hour or more, about 2 hours or more, about 3 hours or more, about 5 hours or more, about 10 hours or more, about 15 hours or more, about 20 hours or more, about 24 hours or more, about 30 hours or less, about 35 hours or less, about 40 hours or less, about 45 hours or less, about 48 hours or less, or any value encompassed by these endpoints.

[0056] This reaction can be carried out not only continuously but also discontinuously or semi-continuously, and is particularly suitable for reactions on an industrial scale.

[0057] The resulting product can be separated from the catalyst by known procedures, such as distillation under reduced pressure. The remaining catalyst can be recycled. EXAMPLES

[0058] All reactions were carried out under inert atmosphere in a N2-filled glove box unless otherwise noted. All glassware was oven-dried before use. Pseudoionone (technical grade, mixture of isomers, GC and 1 Ru(COD)(met)2, and anhydrous methanol were purchased from Sigma-Aldrich. Rh(CO)2(acac) was synthesized using literature procedures (Inorganic Synthesis, 2004, 34, 128). Ligands were purchased from Sigma-Aldrich or Strem Chemicals, Combi-blocks, Alfa Aesar, or Acros (xantphos CAS:161265-03-8, dpephos CAS:166330-10-5, dppm CAS:2071-20-7, dppe CAS:1663-45-2, dppp CAS:6737-42-4, dppb CAS:7688-25-7, dppf CAS:12150-46-8, binap CAS:98327-87-8, spanphos CAS:556797-94-5, P(OPh)3CAS:101-02-0, P(OMe)3CAS:121-45-9, monophos (CAS: 252288-04-3, PPh3 CAS: 603-35-0, P(4-OMeC6H4)3 CAS: 855-38-9, P(3,5-CF3-C6H3)3P CAS: 175136-62-6, PPhMe2672-66-2, PCy3 CAS: 2622-14-2, SPhos CAS 657408-07-6, dippf CAS 97239-80-0). A Parr high pressure reactor (Series 4750 vessel with split ring closure) was used for the hydrogenation. Unless otherwise stated, yields and conversions were determined by gas chromatography using an Agilent J&W HP-5 or DB-5MS column (30 m) with durene as an internal standard.

[0059] Example 1: General procedure for Rh-catalyzed hydrogenation of pseudoionone on a 0.2 mmol scale The pseudoionone was reduced according to Scheme 2 below. [ka]

[0060] In a N2-filled glove box, a stock solution was prepared by mixing Rh(CO)2(acac) (0.004 mmol, 1.0 mg) and xantphos (0.0042 mmol, 2.4 mg) in a 1:1.05 molar ratio in methanol (MeOH) (2 mL) for 30 min at room temperature. An aliquot of the catalyst solution (1.0 mL, 0.002 mmol) was transferred to a vial (1 dram) containing pseudoionone (72% E, 0.2 mmol, 38.4 mg) and durene (5–10 mg) in MeOH (1.0 mL). A stir bar was added to the mixture and the vial was sealed with a PTFE-lined cap. After the PTFE-lined cap was pierced with an 18-gauge needle, the vial was placed in a high-pressure reactor. The high-pressure reactor was sealed and removed from the glove box. The N2 atmosphere of the reactor was replaced with H2 by charging to 600-800 psi and then carefully releasing the pressure, and this process was repeated two more times. The reaction mixture was stirred under the corresponding H2 pressure (700-1000 psi). Pressures as low as 100 psi could be used to obtain similar results.

[0061] To determine the crude yield, after the reaction was complete, a small aliquot (approximately 10 μL) of the reaction mixture was removed and added to a gas chromatography (GC) vial charged with ethyl acetate (EtOAc) and analyzed by GC to determine the conversion and yield, which was greater than 99% and 97% yield (72%E, 28%Z). [GC conditions: HP-5 or DB-5MS, 100-300 °C, 9 min; retention time on HP-5: pseudoionone: t (3E,5Z) =3.01 min, t (3E,5E) = 3.24 min; Geranylacetone: t (5Z) =2.57 min, t (5E) = 2.65 min. Retention time on DB-5MS: Pseudoionone: t (3E,5Z) =3.21 min, t (3E,5E) = 3.46 min; Geranylacetone: t (5Z) =2.74 min, t (5E)= 2.830 min. Molar response factors compared to durene internal standard: pseudoionone: 1.1; geranylacetone: 1.2.

[0062] Three other catalysts were used under the same conditions as above. The catalysts and results are shown in Table 1 below.

[0063] [Table 1]

[0064] Example 2: Reduction of catalyst loading at high temperatures In this example, pseudoionone (72%E, 0.2 mmol, 38.4 mg) was selectively reduced using the same general procedure on a 0.2 mmol scale as above. The catalyst was 0.25 mol% Rh(CO)2(acac) containing 0.53 mol% P(OPh)3. The reaction was stirred at 50 °C for 24 h.

[0065] The yield was determined as above and showed a yield of 92% and a conversion of over 99%.

[0066] Example 3: Rh-catalyzed hydrogenation of pseudoionone, 1 mmol scale In a N2-filled glove box, a stock solution was prepared by mixing Rh(CO)2(acac) (0.011 mmol, 2.8 mg) and xantphos (0.012 mmol, 6.7 mg) in a 1:1.05 molar ratio in MeOH (5.5 mL) for 30 min at room temperature. The catalyst solution (5 mL, 0.01 mmol) was transferred to a 4-dram vial charged with MeOH (5 mL) containing pseudoionone (72% E, 1 mmol, 192.3 mg) and durene (25 mg). A stir bar was added to the mixture and the vial was sealed with a PTFE-lined cap. The PTFE-lined cap was pierced with five 18-gauge needles before the vial was placed in a high-pressure reactor. Alternatively, an 8-dram vial without a cap may be used.

[0067] The high-pressure reactor was sealed and removed from the glove box. The N2 atmosphere of the reactor was replaced with H2 by charging to 600-800 psi and then carefully releasing the pressure, and this process was repeated two more times. The reaction mixture was stirred under the corresponding H2 pressure (1000 psi).

[0068] To determine the crude yield, after the reaction was complete, a small aliquot (approximately 10 uL) of the reaction mixture was removed and added to a GC vial charged with EtOAc and analyzed by GC to determine the conversion and yield, which was greater than 99% conversion and 96% yield (72% E, 28% Z).

[0069] Example 4: Ligand Screen Using the procedure described in Example 1 (yield and conversion by GC), pseudoionone (72%E, 0.2 mmol, 38.4 mg) was treated with Rh(CO)2acac (1 mol%) in conjunction with various bisphosphines and phosphine ligands. In each case, the reactions were carried out at 20 °C under 1000 psi of H2 at a concentration of 0.1 M in MeOH as shown in Scheme 3. [ka]

[0070] The ligands tested, along with the yields and conversions, are shown below in Table 2. Unless otherwise stated, the ratio of rhodium complex to ligand was 1:1 for bisphosphines and 1:2 for monophosphines.

[0071] [Table 2]

[0072] Example 5: Reaction Condition Screen Using the procedure described in Example 1, pseudoionone (72% E, 0.2 mmol, 38.4 mg) was treated with Rh(CO)2acac (1 mol%) and xantphos (1%) as shown in Scheme 4. [ka]

[0073] Various solvents, pressures, temperatures, and reaction times were tested, and the conditions and results are shown in Table 3 below.

[0074] [Table 3]

[0075] Example 6: Catalytic Screen Using the procedure described in Example 1, pseudoionone (72% E, 0.2 mmol, 38.4 mg) was treated with a 1 mol % amount of a transition metal complex and xantphos (1%) as shown in Scheme 5. [ka]

[0076] In all cases, the reaction pressure was 1000 psi under H2 atmosphere; the reaction concentration was 0.1 M in methanol; and the reaction temperature was 20° C. A variety of transition metal complexes were tested, as shown in Table 4 along with the conversions and yields.

[0077] [Table 4]

[0078] Example 7: Ruthenium-catalyzed hydrogenation of pseudoionone [ka] The Ru-catalyzed hydrogenation was carried out using the general procedure described in Example 1 (substituting Ru precursor and ligand for Rh precursor and ligand). The reaction mixture was stirred at 70° C. under an atmosphere of H2 at 800 psi pressure. To determine the crude yield, after the reaction was complete, a small aliquot (approximately 10 uL) of the reaction mixture was removed and added to a GC vial charged with EtOAc and analyzed by GC to determine the conversion and yield (dippf: >99% conversion and 92% yield, 72%E).

[0079] Example 8: Optimization of the hydrogenation of pseudoionone with ruthenium catalyst As shown in Scheme 7, pseudoionones were reduced with ruthenium complexes and various ligands under H2 atmosphere at 800 psi. The reaction concentration was 0.2 M in methanol. The reaction was stirred at 70-75 °C for 2-3 h. [ka]

[0080] The different ligands along with the conversion and yield are given in Table 5.

[0081] [Table 5]

[0082] As a further variation, two ligands were tested at a reaction time of 1.5 hours. The results for these further tests are shown in Table 6 below.

[0083] [Table 6]

[0084] Example 9.1: Reaction after preformation of Rh(CO)2acac / xantphos catalyst Rh(CO)2acac (43 mg, 0.17 mmol) and xantphos (140 mg, 0.24 mmol) were dissolved in tetrahydrofuran (THF) (27 ml) and stirred under synthesis gas (H2 / CO=1:1, vol / vol.) at 1160 psi in a 100 ml steel autoclave (V2A steel, manufacturer Premex, magnetically coupled gas dispersion stirrer, 1000 rpm / mm). The reaction was kept at 70 °C for 16 h, then cooled to 25 °C and the pressure was released. Nitrogen was passed through the solution for 2 h. After flushing with nitrogen, pseudoionone (16.2 g, 84.2 mmol) was added to the autoclave through a lock. The reaction pressure was adjusted to 1160 psi with hydrogen and heated to 50 °C. The yield and conversion were determined by gas chromatography (RXI-ms column: 20 m × 0.18 mm / 0.36 μm; 30 min at 100 °C, then increased to 300 °C at 35 °C / h). After 4 h reaction time, a conversion of 97% was observed, with a yield of geranylacetone of 94%.

[0085] Example 9.2: Reaction after Rh(CO)2acac / dppe using preformed catalyst Rh(CO)2acac (43 mg, 0.17 mmol) and dppe (101 mg, 0.25 mmol) were dissolved in texanol (27 ml) and stirred under synthesis gas (H2 / CO=1:1, vol / vol.) at 1160 psi in a 100 ml steel autoclave (V2A steel, manufacturer Premex, magnetically coupled gas dispersion stirrer, 1000 rpm / mm). The reaction was kept at 70 °C for 16 h, then cooled to 25 °C and the pressure was released. Nitrogen was passed through the solution for 2 h. After flushing with nitrogen, pseudoionone (16.2 g, 84.2 mmol) was added to the autoclave through a lock. The reaction pressure was adjusted to 1160 psi with hydrogen and heated to 50 °C. The yield and conversion were determined by gas chromatography (RXI-ms column: 20 m × 0.18 mm / 0.36 μm; 30 min at 100 °C, then increased to 300 °C at 35 °C / h). After 4 h reaction time, a conversion of more than 98% was observed, with a yield of geranylacetone of 97%.

[0086] Example 9.3: Post-reaction of Rh(CO)2acac / PPh3 using preformed catalyst Rh(CO)2acac (43 mg, 0.17 mmol) and PPh3 (135 mg, 0.52 mmol) were dissolved in THF (30 ml) and stirred under synthesis gas (H2 / CO=1:1, vol / vol.) at 1160 psi in a 100 ml steel autoclave (V2A steel, manufacturer Premex, magnetically coupled gas dispersion stirrer, 1000 rpm / mm). The reaction was kept at 70 °C for 16 h, then cooled to 25 °C and the pressure was released. Nitrogen was passed through the solution for 2 h. After flushing with nitrogen, pseudoionone (16.2 g, 84.2 mmol) was added to the autoclave through a lock. The reaction pressure was adjusted to 1160 psi with hydrogen and heated to 50 °C. The yield and conversion were determined by gas chromatography (RXI-ms column: 20 m × 0.18 mm / 0.36 μm; 30 min at 100 °C, then 35 °C / h to 300 °C). After 20 h reaction time, a conversion of more than 98% was observed, with a yield of geranylacetone of 97%.

[0087] Example 10: Reaction after preformation of Rh(CO)2acac / P(OPh)3 catalyst Rh(CO)2acac (43 mg, 0.17 mmol) and P(OPh)3 (155 mg, 0.5 mmol) were dissolved in tetrahydrofuran (THF) (27 ml) and stirred under synthesis gas (H2 / CO=1:1, vol / vol.) at 1160 psi in a 100 ml steel autoclave (V2A steel, manufacturer Premex, magnetically coupled gas dispersion stirrer, 1000 rpm / mm). The reaction was kept at 70 °C for 16 h, then cooled to 25 °C and the pressure was released. Nitrogen was passed through the solution for 2 h. After flushing with nitrogen, pseudoionone (15.2 g, 84.2 mmol) was added to the autoclave through a lock. The reaction pressure was adjusted to 1160 psi with hydrogen and heated to 50 °C. Yield and conversion were determined by gas chromatography. After 20 h reaction time, a conversion of 99% was observed with a yield of geranylacetone of 91%.

[0088] Example 11: Extent of Rh(CO)2acac / xantphos catalyzed reduction In this example, Rh(CO)2acac / xantphos (L:Rh=1:1, MeOH, 1 mol% Rh) was used as a catalyst to reduce various substrates. In all cases, the reactions were carried out under a H2 atmosphere at 1000 psi. The substrates and conditions for each reaction are listed in Table 7 along with the conversion, yield, and isolated yield. The reactions were carried out according to the general procedure described in Example 1 with the variations listed in Table 7. See the Experimental Data section for the isolation protocols for Experiments 11.1-11.9 (compounds 2-9).

[0089] [Table 7]

[0090] Example 12: Extent of Rh(CO)acac / P(OPh) catalyzed reduction In this example, Rh(CO)2acac / P(OPh)3 (L:Rh=2:1, MeOH, 1 mol% Rh) was used as a catalyst to reduce various substrates. In all cases, the reactions were carried out under a H2 atmosphere at 1000 psi. The substrates and conditions for each reaction are listed in Table 8 below, along with the conversion and yield. The reactions were carried out following the general procedure described in Example 1, with the variations listed in Table 8.

[0091] [Table 8]

[0092] Experimental Data for Compounds of Examples 3 and 11 and Table 7 The NMR and high resolution mass spectrometry (HRMS) results for the compounds of Examples 3 and 11 are shown below, along with the specific purification conditions.

[0093] Compound 1, Example 3 [ka] Compound 1 was prepared from pseudoionone (192.3 mg, 1.0 mmol) according to the procedure described in Example 3. The reaction proceeded with >98% conversion and >90% yield (72:28 E / Z ratio) as determined by calibrated GC using durene as an internal standard (ISTD). The product was isolated as a mixture of geometric isomers (5E:5Z=72:28) in 88% yield as a colorless oil after purification by flash column chromatography (2%-18% EtOAc in hexanes). 1 H NMR(CDCl3,500MHz)δ 5.13-5.04(m,2H),2.44(dt J=7.4,7.1Hz,2H),2.30-2.22(m,2H),2.13(s,3H),2.09-2.01(m,2H),2.00-1.94(m,2H),1.67(s,3H),1.61(s,3H),1.59(s,3H); 13 C NMR (CDCl3, 125 MHz, major, E product) δ 208.9, 136.4, 131.5, 124.2, 122.6, 43.8, 39.7, 30.0, 26.7, 25.7, 22.5, 17.7, 16.0; 13 C NMR(CDCl3,125MHz,minor,Z product)δ 208.8,136.5,131.7,124.2,123.4,44.1,31.9,29.9,26.5,25.8,23.4,22.3,17.7;HRMS(EI):C 13 H 22 O[M] + Calculated value: 194.1665. Measured value: 194.1672.

[0094] Compound 2, Example 11.7 [ka] Compound 2 was prepared from the corresponding diene (29.3 mg, 0.21 mmol) at 50° C. following the general procedure described in Example 1. The reaction was 1 H NMR confirmed complete consumption of starting material after 16 h. The product was isolated as a 75:25 mixture of product versus overreduction. 1H NMR(CDCl3,500MHz)δ 5.11-5.06(m,1H),3.67(s,3H),2.36-2.27(m,4H),1.68(s,3H),1.62(s,3H); 13 C NMR(CDCl3,125MHz)δ 173.9,133.2,122.4,51.5,34.3,25.7,23.7,17.7;HRMS(EI):C8H 14 O2[M] + Calculated value: 142.09938. Found value: 142.09963. HRMS (EI): C8H 14 O2[M] + Calculated value: 142.0988. Measured value: 142.0996.

[0095] Compound 3, Example 11.4 [ka] Compound 3 was prepared from the corresponding diene (18 mg, 0.097 mmol, ca. 80:20 Z / E) following the general procedure described in Example 1. The reaction proceeded and was calibrated using durene as the ISTD. 1 There was >98% conversion and 93% yield (5Z:5E = 83:17) as determined by H NMR. The product (only the 5Z isomer) was isolated in 77% yield after purification by thin layer chromatography (10% EtOAc in hexanes). 1 H NMR(CDCl3,500MHz)δ 7.35-7.31(m,2H),7.24(tt,J=7.4,1.4Hz,1H),7.18-7.15(m,2H),5.41(tq,J=7.4,1. 4Hz,1H),2.43(t,J=7.4Hz,2H),2.25(q,J=7.1Hz,2H),2.07(s,3H),2.02-2.01(m,3H); 13 C NMR(CDCl3,125MHz)δ 208.5,141.8,137.7,128.2,127.9,126.7,125.5,44.0,29.8,25.6,23.6;HRMS(EI):C 13 H 16 O[M] + Calculated value: 188.1196. Measured value: 188.1205.

[0096] Compound 4, Example 11.2 [ka] Compound 4 was prepared from the corresponding diene (17.8 mg, 0.096 mmol) following the general procedure described in Example 1. The reaction proceeded and was calibrated using durene as the ISTD. 1 The conversion was greater than 98% and the yield was 95% as determined by H NMR. The product was isolated in 85% (only the 5E isomer) after purification by thin layer chromatography (10% EtOAc in hexanes). 1 H NMR(CDCl3,500MHz)δ 7.37-7.34(m,2H),7.32-7.28(m,2H),7.45-7.21(m,1H),5.71(tq,J=7.2,1.4Hz,1 H),2.60,(t,J=7.4Hz,2H),2.48(q,J=7.4Hz,2H),2.17(s,3H),2.06-2.05(m,3H); 13 C NMR(CDCl3,125MHz)δ 208.4,143.7,136.0,128.2,126.7,126.4,125.7,43.4,30.0,23.2,15.9;HRMS(EI):C 13 H 16 O[M] + Calculated value: 188.1196. Measured value: 188.1202.

[0097] Compound 5, Example 11.6 [ka] Compound 5 was prepared from β-ionone (39.5 mg, 0.21 mmol) at 40° C. following the general procedure described in Example 1. The reaction proceeded to over 98% conversion with no by-products. 1 Not observed by H NMR. The product was isolated in 99% after purification by silica plug (25% EtOAc in hexanes). 1H NMR(CDCl3,500MHz)δ 2.52-2.47(m,2H),2.28-2.23(m,2H),2.14(s,3H),1.90(t,J=6.4Hz,2H),1.59-1.53(m,5H),1.43-1.39(m,2H),0.97(s,6H); 13 C NMR(CDCl3,125MHz)δ 209.1,136.0,127.8,44.6,39.8,35.1,32.8,29.8,28.5,22.3,19.8,19.5;HRMS(EI):C 13 H 22 O[M] + Calculated value: 194.1665. Measured value: 194.1672.

[0098] Compound 6, Example 11.5 [ka] Compound 6 was prepared from α-ionone (38.5 mg, 0.20 mmol) at 40° C. following the general procedure described in Example 1. The reaction proceeded as follows: 1 Over 98% conversion by H NMR, no by-products observed. The product was isolated in 99% after purification through a silica plug (25% EtOAc in hexanes). 1 H NMR (CDCl3, 500MHz) δ 5.33(m,1H),2.461(dd,J=12.8,9.9Hz,1H),2.460(d,J=10.2Hz,1H),2.13(s,3 H),1.99-1.94(m,2H),1.76(ddt,J=14.9,10.4,5.6Hz,1H),1.66(dtd,J=2.1,1. 8,0.5Hz,3H),1.60(dddd,J=19.0,9.9,6.7,4.5Hz,1H),1.47(dd,J=4.5,4.5Hz, 1H),1.40(ddd,J=17.0,9.4,7.7Hz,1H),1.13(m,1H),0.91(s,3H),0.87(s,3H); 13 C NMR(CDCl3,125MHz)δ 209.2,135.6,121.1,48.5,43.8,32.6,31.6,30.0,27.7,27.6,24.4,23.6,23.0;HRMS(EI):C 13 H22 O[M] + Calculated value: 194.1665. Measured value: 194.1670.

[0099] Compound 7, Example 11.3 [ka] Compound 7 was prepared from the corresponding diene (17.2 mg, 0.1 mmol) following the general procedure described in Example 1 (0.1 mmol scale procedure) in 0.5 h. 1 H NMR diene conversion: >98%, crude yield: 84%. Isolated in 83% yield by silica column chromatography (10% EtOA in hexanes). 1 H NMR(CDCl3,700MHz)δ 7.33-7.28(m,4H),7.21-7.19(m,1H),6.41(d,J=15.6Hz,1H),6.20(dt,J =16.0,7.0Hz,1H),2.61(t,J=7.6Hz,2H),2.51-2.49(m,2H),2.17(s,3H); 13 C NMR(CDCl3,125MHz)δ 208.1,137.5,130.8,128.9,128.6,127.2,126.1,43.3,30.1,27.2;HRMS(EI):C 12 H 14 O[M] + Calculated value: 174.1039. Measured value: 174.1044.

[0100] Compound 9, Example 11.9 [ka] Compound 9 was prepared from the corresponding diene (23.4 mg, 0.1 mmol) following the general procedure described in Example 1 (0.1 mmol scale procedure) in 4 h. 1 H NMR diene conversion: 85%, crude yield: 84%. Isolated in 84% yield by silica column chromatography (2% EtOA in hexanes). 1H NMR(CDCl3,500MHz)δ 8.00-7.97(m,2H),7.59-7.55(m,1H),7.50-7.45(m,2H),7.36-7.32(m,2H),7.31-7.27(m,2H),7.22-7.1 8(m,1H),6.47(d,J=15.8Hz,1H),6.30(dt,J=15.7,6.8Hz,1H),3.16(t,J=7.6Hz,2H),2.69-2.64(m,2H); 13 C NMR(CDCl3,125MHz)δ 199.4,137.5,136.9,133.1,130.9,129.2,128.7,128.6,128.1,127.1,126.1,38.3,27.6;HRMS(EI):C 17 H 16 O[M] + Calculated value: 236.1196. Measured value: 236.1199.

[0101] Comparative example A: Finally, known conditions were tested using pseudoionone as substrate, as shown in Scheme 8 below. [ka] The reaction mixture was analyzed at two different time points and the results are shown in Table 9 below.

[0102] [Table 9]

[0103] As can be seen, the known conditions do not provide acceptable conversions and selectivities for the pseudoionones.

[0104] Embodiment Embodiment 1 is a method for the selective hydrogenation of a dienone, the method comprising: 1) combining a dienone with one or more solvents; 2) adding a catalyst to the mixture of the dienone and the solvent to provide a reaction mixture; and 3) contacting the reaction mixture with an atmosphere comprising hydrogen (H2); the catalyst comprises one or more transition metals and one or more ligands, and the reaction is conducted in the absence of pyridines, pyrazines, quinolines, and quinoxalines.

[0105] Embodiment 2 is the method of embodiment 1, wherein the one or more transition metals are selected from the group including ruthenium, rhodium, platinum, palladium, and nickel.

[0106] Embodiment 3 is the method of embodiment 1 or embodiment 2, wherein the one or more transition metals comprises a rhodium or ruthenium metal complex.

[0107] Embodiment 4 is the method of any one of embodiments 1-3, wherein the one or more transition metals comprise Rh(CO)2acac, Rh(III) acetate, or [Ru(COD)(2-methylallyl)2].

[0108] Embodiment 5 is the method of embodiment 4, wherein the one or more transition metals comprises Rh(CO2)acac.

[0109] Embodiment 6 is the method of embodiment 4, wherein the one or more transition metals comprises [Ru(COD)(2-methylallyl)2].

[0110] Embodiment 7 is a compound in which the ligand is 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), bis[(2-diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane) (SPANPhos), triphenylphosphite (P(OPh)3), trimethylphosphite (P(OMe)3), triethylphosphite (P(OEt)3), (3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine (MonoPhos), 6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-[1,1'-biphenyl]-2,2'-diyl] 7. The method of any one of the preceding claims, wherein the aryl group is selected from the group comprising)]bis(6H-dibenzo[d,f][1,3,2]dioxaphosphepine) (BiPhePhos), (R,R)Chiraphos, (S,S)Chiraphos, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), triphenylphosphine (PPh3), tris(4-methoxyphenyl)phosphane, tris(3,5-bis(trifluoromethyl)phenyl)phosphane, 1,1'-bis(diisopropylphosphino)ferrocene (dippf), and methyldiphenylphosphane.

[0111] Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the one or more ligands are selected from the group including 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), 1,2-bis(diphenylphosphino)ethane (dppe), (3,5-dioxa-4-phosphacyclohepta[2,1-a.3,4-a′]dinaphthalen-4-yl)dimethylamine (MonoPhos), (R,R)Chiraphos, (S,S)Chiraphos, and triphenylphosphite.

[0112] Embodiment 9 is the method of any one of embodiments 1 to 7, wherein the one or more ligands are selected from the group consisting of 1,1′-bis(diisopropylphosphino)ferrocene (dippf) and 1,4-bis(diphenylphosphino)butane (dppb).

[0113] Embodiment 10 is the method of any one of embodiments 1-9, wherein the one or more ligands are combined with the transition metal or transition metal complex in a molar ratio of about 1:1 to about 10:1.

[0114] Embodiment 11 is the method of any one of embodiments 1-10, wherein the transition metal complex is present in the reaction in an amount of about 0.01 mol % to about 1.0 mol %.

[0115] Embodiment 12 is the method of any one of embodiments 1 to 11, wherein the ligand is present in the reaction in an amount of about 0.01 mol % to about 10.0 mol %.

[0116] Embodiment 13 is the method of any one of embodiments 1-12, wherein the one or more solvents are selected from the group consisting of methanol, 1-butanol, 1-propanol, 2-propanol, tetrahydrofuran, toluene, ethyl acetate, and ethanol.

[0117] Embodiment 14 is the method of any one of embodiments 1 to 13, further comprising one or more co-solvents.

[0118] Embodiment 15 is the method of embodiment 14, wherein the co-solvent comprises an alkylbenzene.

[0119] Embodiment 16 is the method of any one of embodiments 1 to 15, wherein the hydrogen atmosphere is at a pressure of about 1 bar to 100 bar, preferably 5 bar to 90 bar, more preferably 10 bar to 80 bar.

[0120] Embodiment 17 is the method of embodiment 16, wherein the hydrogen atmosphere further comprises carbon monoxide in an amount from about 1 ppm to about 2000 ppm.

[0121] Embodiment 18 is an embodiment in which the dienone is a (2,3) / (4,5) unsaturated dienone of formula I, [ka] In the formula, R 1 is C1-C6 alkyl, C1-C6 alkoxy, or R 2 and R 2 is hydrogen, C1-C6 alkyl, or R 1 and R 3 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 4 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 5 and R 5 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 4 and R is a bond forming an optionally substituted 5- or 6-membered ring.

[0122] Embodiment 19 is a compound comprising R 1 is C1-C6 alkyl or C1-C6 alkoxy; R 2 is hydrogen or C1-C6 alkyl; R3 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 4 is hydrogen, C1-C6 alkyl, C1-C 10 19. The method of embodiment 18, wherein R is alkenyl, or aryl.

[0123] Embodiment 20 is a method for producing a compound according to the present invention 1 is C1-C6 alkyl; R 2 is hydrogen; R 3 is C1-C6 alkyl; R 4 is C1~C 10 19. The method of embodiment 18, wherein said alkenyl is alkenyl.

[0124] Embodiment 21 is the method of embodiment 18, wherein the (2,3) / (4,5) unsaturated dienone comprises a β-ionone or a pseudoionone.

[0125] In embodiment 22, the dienone is a (2,3) / (5,6) unsaturated dienone of formula II shown below: [ka] In the formula, R 6 is C1-C6 alkyl or C1-C6 alkoxy; R 7 is hydrogen or C1-C6 alkyl; R 8 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 9 is hydrogen, C1-C6 alkyl, C1-C 10 alkenyl, or aryl; R 10 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 11 and R 11 is hydrogen, C1-C6 alkyl, C1-C 10 Alkenyl, aryl, or R 10 and R is a bond forming an optionally substituted 5- or 6-membered ring.

[0126] Embodiment 23 is the method of embodiment 22, wherein the (2,3) / (5,6) unsaturated dienone comprises an α-ionone.

[0127] Embodiment 24 is the method of any one of embodiments 1 to 23, wherein the dienone is monohydrogenated.

[0128] Embodiment 25 is a process for preparing an active catalyst comprising Rh(CO)2acac or Ru(COD)met2 in combination with 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), bis[(2-diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane) (SPANPhos), triphenylphosphite (P(OPh)3), trimethylphosphite (P(OMe)3), (3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine (MonoPho 25. The method of any one of embodiments 1-24, comprising one or more of: 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), triphenylphosphine (PPh3), tris(4-methoxyphenyl)phosphane, tris(3,5-bis(trifluoromethyl)phenyl)phosphane, 1,1'-bis(diisopropylphosphino)ferrocene (dippf), and methyldiphenylphosphane.

[0129] Embodiment 26 is the method of any one of embodiments 1 to 25, wherein the reaction is carried out substantially in the absence of pyridine, pyrazine, quinoline, and quinoxaline.

[0130] Embodiment 27 is the method according to any one of embodiments 1 to 26, wherein the catalyst is preformed by mixing the Rh-precursor and the ligand in a solvent under an inert atmosphere or under an atmosphere of hydrogen or carbon monoxide or a mixture of hydrogen and carbon monoxide in any ratio, at a pressure ranging from 1 bar to 100 bar.

[0131] Embodiment 28 is the method of any one of embodiments 1 to 27, wherein the catalyst is a carbonyl-containing Rh-phosphine catalyst of the type L2Rh(CO)H or L3Rh(CO)H, where L is a monodentate phosphine or monodentate phosphite.

[0132] Embodiment 29 is the method of any one of embodiments 1 to 27, wherein the catalyst is a carbonyl-containing Rh-phosphine catalyst of the type L'Rh(CO) or L'Rh(CO)2H, where L' is a bidentate phosphine or a bidentate phosphite.

Claims

1. 1. A process for the selective monohydrogenation of a dienone with hydrogen, comprising the steps of: 1) combining a dienone with one or more solvents or without solvent; 2) adding a catalyst to a mixture of dienone and a solvent, or to a pure dienone, to provide a reaction mixture; 3) The reaction mixture is cooled to room temperature with hydrogen (H ２ and contacting the mixture with an atmosphere containing the Including; The catalyst comprises a transition metal and one or more phosphine ligands and / or one or more neutral or anionic ligands; The process wherein the reaction is carried out in the absence of pyridine, pyrazine, quinoline, and quinoxaline.

2. The method of claim 1 , wherein the transition metal is selected from the group consisting of ruthenium, rhodium, platinum, palladium, and nickel.

3. The method of claim 1 or 2, wherein the catalyst comprises a rhodium or ruthenium metal complex.

4. The catalyst is formed by reacting a transition metal-containing precursor with the ligand to form a transition metal-ligand complex, the metal-containing precursor being Rh(CO) ２ acac, Rh(III) acetate, or [Ru(COD)(2-methylallyl) ２ The method according to any one of claims 1 to 3, comprising:

5. The transition metal-containing precursor is Rh(CO). ２ 5. The method of claim 4, wherein the compound is acac.

6. The transition metal-containing precursor is [Ru(COD)(2-methylallyl) ２ 5. The method according to claim 4, wherein

7. The one or more ligands may be CO, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), bis[(2-diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino). butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane) (SPANPhos), triphenylphosphite (P(OPh) ３ ), trimethyl phosphite (P(OMe) ３ ), triethyl phosphite (P(OEt) ３ ), (3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine (MonoPhos), 6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-[1,1'-biphenyl]-2,2'-diyl)bis(oxy)]bis(6H-dibenzo[d,f][1,3,2]dioxaphosphepine) (BiPhePhos), (R,R)Chiraphos, (S,S)Chiraphos, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), triphenylphosphine (PPh ３ 7. The method of any one of claims 1 to 6, wherein the aryl group is selected from the group consisting of tris(4-methoxyphenyl)phosphane, tris(3,5-bis(trifluoromethyl)phenyl)phosphane, 1,1'-bis(diisopropylphosphino)ferrocene (dippf), and methyldiphenylphosphane.

8. The one or more ligands may be 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), 1,2-bis(diphenylphosphino)ethane (dppe), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis(diphenylphosphino)ferrocene (dppf), (3,5-dioxa-4-phosphacyclohepta[2,1-a.3,4-a′]dinaphthalen-4-yl)dimethylamine (MonoPhos), (R,R)Chiraphos, (S,S)Chiraphos, and triphenylphosphite (PPh). ３ The method according to any one of claims 1 to 7, wherein the compound is selected from the group comprising:

9. The method according to any one of claims 1 to 7, wherein the one or more ligands are selected from the group comprising 1,1'-bis(diisopropylphosphino)ferrocene (dippf) and 1,4-bis(diphenylphosphino)butane (dppb).

10. The method of any one of claims 1 to 9, wherein the one or more ligands are combined with the transition metal or transition metal complex in a molar ratio of about 1:1 to about 10:

1.

11. 11. The method of any one of claims 1 to 10, wherein the transition metal complex is present in the reaction in an amount of from about 0.01 mol % to about 1.0 mol %.

12. 12. The method of any one of claims 1 to 11, wherein the ligand is present in the reaction in an amount from about 0.01 mol % to about 10.0 mol %.

13. 13. The method of any one of claims 1 to 12, wherein the one or more solvents are selected from the group consisting of methanol, 1-butanol, 1-propanol, 2-propanol, 1-hexanol, 1-decanol, 1-nonanol, texanol (3-hydroxy-2,2,4-trimethylpentyl isobutyrate), tetrahydrofuran, 2-methyl-tetrahydrofuran, MTBE, toluene, ethyl acetate, and ethanol.

14. The method of any one of claims 1 to 13, wherein the one or more solvents are selected from the group consisting of methanol, 1-butanol, 1-propanol, 2-propanol, tetrahydrofuran, toluene, ethyl acetate, and ethanol.

15. The method of any one of claims 1 to 14, further comprising one or more co-solvents.

16. The method of claim 15 , wherein the co-solvent comprises an alkylbenzene.

17. A method according to any one of the preceding claims, wherein the hydrogen atmosphere is at a pressure of about 1 bar to 100 bar, preferably 5 bar to 90 bar, more preferably 10 bar to 80 bar.

18. The process according to any one of claims 1 to 17, wherein the reaction is carried out at a temperature of from about 10°C to about 100°C, preferably from 10°C to 90°C, more preferably from 20°C to 80°C, particularly preferably from 30°C to 70°C.

19. The method of claim 17, wherein the hydrogen atmosphere further comprises carbon monoxide in an amount from about 1 ppm to about 2000 ppm.

19. The dienone is a (2,3) / (4,5) unsaturated dienone of formula I, 【Chemistry 1】 In the formula, R １ is C １ ~C ６ Alkyl, C １ ~C ６ Alkoxy or R ２ and a bond forming an optionally substituted 5- or 6-membered ring; R ２ is hydrogen, C １ ~C ６ Alkyl, or R １ and a bond forming an optionally substituted 5- or 6-membered ring; R ３ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ alkenyl, or aryl; R ４ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ Alkenyl, aryl, or R ５ and a bond forming an optionally substituted 5- or 6-membered ring; R ５ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ Alkenyl, aryl, or R ４ and a bond forming an optionally substituted 5- or 6-membered ring; 19. The method according to any one of claims 1 to 18.

20. R １ C １ ~C ６ Alkyl or C １ ~C ６ is alkoxy; R ２ is hydrogen or C １ ~C ６ is alkyl; R ３ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ alkenyl, or aryl; R ４ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ alkenyl, or aryl; 20. The method of claim 19.

21. R １ is C １ ~C ６ is alkyl; R ２ is hydrogen; R ３ is C １ ~C ６ is alkyl; R ４ is C １ ~C １０ is alkenyl, 20. The method of claim 19.

22. 20. The method of claim 19, wherein the (2,3) / (4,5) unsaturated dienone comprises β-ionone, 6-methyl-3,5-heptadien-2-one, or pseudoionone.

23. The dienone is a (2,3) / (5,6) unsaturated dienone of formula II shown below: 【Chemistry 2】 In the formula, R ６ is C １ ~C ６ Alkyl or C １ ~C ６ is alkoxy; R ７ is hydrogen or C １ ~C ６ is alkyl; R ８ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ alkenyl, or aryl; R ９ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ alkenyl, or aryl; R １０ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ Alkenyl, aryl, or R １１ and a bond forming an optionally substituted 5- or 6-membered ring; R １１ is hydrogen, C １ ~C ６ Alkyl, C １ ~C １０ Alkenyl, aryl, or R １０ and a bond forming an optionally substituted 5- or 6-membered ring; 19. The method according to any one of claims 1 to 18.

24. 24. The method of claim 23, wherein the (2,3) / (5,6) unsaturated dienone comprises an α-ionone.

25. The active catalyst is Rh(CO) ２ acac or Ru(COD)met ２ and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos), bis[(2-diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dp pb), 1,1'-bis(diphenylphosphino)ferrocene (dppf), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane) (SPANPhos), triphenylphosphite (P(OPh) ３ ), trimethyl phosphite (P(OMe) ３ ), (3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine (MonoPhos), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), triphenylphosphine (PPh ３ ), tris(4-methoxyphenyl)phosphane, tris(3,5-bis(trifluoromethyl)phenyl)phosphane, 1,1′-bis(diisopropylphosphino)ferrocene (dippf), and one or more of methyldiphenylphosphane.

26. The method of any one of claims 1 to 25, wherein the reaction is carried out substantially in the absence of pyridine, pyrazine, quinoline, and quinoxaline.

27. 27. The method according to any one of claims 1 to 26, wherein the catalyst is preformed by mixing the Rh-precursor and the ligand in a solvent under an inert atmosphere or under an atmosphere of hydrogen or carbon monoxide or a mixture of hydrogen and carbon monoxide in any ratio at a pressure ranging from 1 bar to 100 bar.

28. The method of any one of claims 1 to 27, wherein the catalyst comprises a transition metal, a phosphine ligand, and a carbonyl ligand.

29. The catalyst is L ２ Rh(CO)H or L ３ 29. The process according to any one of claims 1 to 28, wherein the carbonyl-containing Rh-phosphine catalyst is of the type Rh(CO)H, L being a monodentate phosphine or a monodentate phosphite.

30. The catalyst is L'Rh(CO) or L'Rh(CO) ２ The process according to any one of claims 1 to 28, wherein the Rh-phosphine catalyst is of type H and L' is a bidentate phosphine or a bidentate phosphite.

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