Process for producing 6-dimethylaminomethyl-phenyl-cyclohexane-1,3-diols

1. A process for producing compounds corresponding to formulas III or IV or mixtures thereof:

wherein R represents hydrogen or C 1 -C 4 alkyl,

said process comprising hydrogenating the keto groups of compounds corresponding to formulas I or II or mixtures thereof:

wherein the hydrogenation is effected:

a) with hydrogen in the presence of platinum dioxide, platinum(IV)chloride, platinum(II)chloride or Raney nickel in the heterogeneous phase; or

b) with hydrogen in the presence of a rhodium, iridium or ruthenium complex with at least one chiral diphosphine ligand, diamine ligand or phosphinite ligand in the homogeneous phase; or

c) with an alkali metal trialkyl borohydride or an alkali metal trialkyl aluminium hydride.

2. A process according to claim 1 , wherein R represents hydrogen or methyl.

3. A process according to claim 1 , wherein the ratio of diastereomers of formulas III and IV to diastereomers of formulas V and VI

is at least 75:25.

4. A process according to claim 1 , wherein the hydrogenation is effected in accordance with a) or b) at a hydrogen pressure of from 10 5 to 2×10 7 Pascal.

5. A process according to claim 1 , wherein the hydrogenation is effected at a temperature of from −80 to 150° C.

6. A process according to claim 1 , wherein

the hydrogenation is effected using platinum dioxide in an amount of from 1 to 15% by weight based on the weight of the compounds of formulas I and II, or

the hydrogenation is effected using Raney nickel in an amount of from 1 to 50% by weight based on the weight of the compounds of formulas I and II, or

the hydrogenation is effected using a rhodium, iridium or ruthenium complex with chiral diphosphines in an amount of from 0.0001 to 10% by weight based on the weight of the compounds of formulas I and II, or

the hydrogenation is effected using an alkali metal trialkyl borohydride or alkali metal trialkyl aluminium hydride in an amount of from 0.5 to 1.5 equivalents based on the compounds of formulas I and II.

7. A process according to claim 1 , wherein

the hydrogenation is effected using platinum dioxide in an alcohol selected from the group consisting of methanol, ethanol and mixtures thereof, or

the hydrogenation is effected using Raney nickel in an alcohol, carboxylic acid ester, aromatic hydrocarbon or a mixture of two or more thereof.

8. A process according to claim 1 , wherein the hydrogenation is effected in the presence of a rhodium, iridium or ruthenium complex with at least one diphosphine ligand corresponding to a secondary phosphino-skeleton-secondary phosphino formula, said ligand forming a five to ten-membered ring with the metal atom and having a skeleton containing from 2 to 30 carbon atoms, and optionally heteroatoms independently selected from the group consisting of O, S, NH and N—C 1 -C 4 alkyl, and optionally transition metal atoms.

9. A process according to claim 8 , wherein the skeleton consists of bivalent radicals of alkanes, heteroalkanes, alkenes, cycloalkanes, cycloalkenes, heterocycloalkanes, heterocycloalkenes, bicycloalkanes, bicycloheteroalkanes, spirobiscycloalkanes, spirobiscycloheteroalkanes, arylenes, heteroarylenes, bisarylenes, bisheteroarylenes, metalocenes, and the radicals are unsubstituted or substituted one or more times with substituents selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkylthio, C 4 -C 8 cycloalkyl, phenyl, benzyl, phenoxy, benzyloxy, phenylthio, benzylthio, halogen, OH, tri(C 1 -C 6 alkyl)silyl, secondary amino, —CO 2 H, —SO 3 H, —CO 2 R′, —SO 3 R′, —O—C(O)—R′, —NH—C(O)R′, —O—SO 3 —R′ and —NH—SO 3 R′;

where R′ represents C 1 -C 6 alkyl, C 4 -C 8 cycloalkyl, phenyl or benzyl.

10. A process according to claim 9 , wherein the skeleton consists of bivalent radicals of ferrocenes.

11. A process according to claim 8 , wherein the secondary phosphine groups contain the same or different hydrocarbon radicals as the substituents, and the two secondary phosphine groups in the diphosphine ligand are the same or different.

12. A process according to claim 8 , wherein the two secondary phosphino radicals are independently selected from non-cyclic secondary phosphines selected from the group consisting of —P(C 1 -C 6 alkyl) 2 , —P(C 5 -C 8 cycloalkyl) 2 , —P(C 7 -C 8 -bicycloalkyl) 2 , —P(o-furyl) 2 , —P(C 6 H 5 ) 2 , —P[2-(C 1 -C 6 alkyl)C 6 H 4 ] 2 , —P[3-(C 1 -C 6 alkyl)C 6 H 4 ] 2 , —P[4-(C 1 -C 6 alkyl)C 6 H 4 ] 2 , —P[2-(C 1 -C 6 alkoxy)C 6 H 4 ] 2 , —P[3-(C 1 -C 6 alkoxy)C 6 H 4 ] 2 , —P[4-(C 1 -C 6 alkoxy)C 6 H 4 ] 2 , —P[2-(trifluoromethyl)C 6 H 4 ] 2 , —P[3-(trifluoromethyl)C 6 H 4 ] 2 , —P[4-(trifluoromethyl)C 6 H 4 ] 2 , —P[3,5-bis(trifluoromethyl)C 6 H 3 ] 2 , —P[3,5-bis(C 1 -C 6 alkyl) 2 C 6 H 3 ] 2 , —P[3,5-bis(C 1 -C 6 alkoxy) 2 C 6 H 3 ] 2 , and —P[3,5-bis(C 1 -C 6 alkyl) 2 -4-(C 1 -C 6 alkoxy)C 6 H 2 ] 2 ; and cyclic phosphines selected from the group consisting of

which are each unsubstituted or substituted one or more times with C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkoxy-C 1 -C 2 alkyl, phenyl, benzyl, benzyloxy, or C 1 -C 4 alkylidene-dioxyl.

13. A process according to claim 8 , wherein the diphosphine ligands are selected from the group consisting of ligands corresponding to formulas VII to XV:

where X 1 and X 2 represent the same or different secondary phosphino, R 3 is C 1 -C 4 alkoxy or C 1 -C 4 alkyl, R 4 is hydrogen or is the same as R 3 , or R 3 and R 4 , together with the carbon atoms to which they are bound, form a five or six-membered carbocyclic ring or a heterocyclic ring with heteroatoms independently selected from the group consisting of O, S, —N═ and —N(C 1 -C 4 alkyl);

where X 1 and X 2 represent the same or different secondary phosphino, R 6 is secondary amino, and R 5 represents (C 1 -C 6 alkyl), cyclohexyl, phenyl or benzyl;

where X 1 and X 2 represent the same or different secondary phosphino, and R 7 is —OH, C 1 -C 10 alkoxy, phenoxy, benzyloxy or C 1 -C 8 -acyloxy;

where X 1 and X 2 represent the same or different secondary phosphino, and R 8 represents C 1 -C 6 alkyl, cyclohexyl, phenyl or benzyl;

where X 1 and X 2 represent the same or different secondary phosphino, and R 9 is hydrogen, or a group —CH(R 7 )R 8 , where R 7 is —OH, C 1 -C 10 alkoxy, phenoxy, benzyloxy or C 1 -C 8 -acyloxy; and R 8 is C 1 -C 6 alkyl, cyclohexyl, phenyl or benzyl;

where X 1 and X 2 represent the same or different secondary phosphino, and R 8 is C 1 -C 6 alkyl, cyclohexyl, phenyl or benzyl;

where X 1 represents secondary phosphino, and R 10 is C 1 -C 6 alkyl, cyclohexyl, phenyl or benzyl;

where X 1 and X 2 represent the same or different secondary phosphino; and

where R 11 and R 12 represent hydrocarbon radicals having from 1 to 20 carbon atoms which are unsubstituted or substituted with C 1 -C 6 alkyl and/or C 1 -C 6 alkoxy.

14. A process according to claim 13 , wherein said ligand is selected from the group consisting of ligands L1 to L26:

L1: formula VII, R 3 and R 4 together are —CH═CH—CH═CH, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L2: formula XIII, R 10 is tert-butyl, X 1 is —P(C 6 H 5 ) 2 ;

L3: formula XIII, R 10 is iso-propyl, X 1 is —P(C 6 H 5 ) 2 ;

L4: formula XIII, R 10 is iso-propyl, X 1 is —P[(3,5-dimethyl-4-methoxyC 6 H 2 )] 2 ;

L5: formula XIII, R 10 is phenyl, X 1 is —P(C 6 H 5 ) 2 ;

L6: formula VII, R 3 and R 4 together are —O—CH 2 CH 2 —N(CH 3 ), X 1 and X 2 are each —P[(3,5-dimethyl-C 6 H 3 )] 2 ;

L7: formula VII, R 3 and R 4 together are —O—CF 2 —O, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L8: formula XII, R 8 is methyl, X 1 is —P(C 6 H 5 ) 2 , X 2 is —P[(3,5-di(trifluoromethyl)-C 6 H 3 )] 2 (R,R-configuration);

L9: formula XIV, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L10: formula X, R 8 is methyl, X 1 is —P[(3,5-dimethyl-C 6 H 3 )] 2 , X 2 is —P[(3,5-di(trifluoromethyl)-C 6 H 3 )] 2 ;

L11: formula VII, R 3 and R 4 together are —O—CH 2 CH 2 —N(CH 3 ), X 1 and X 2 are each —P[(3,5-dimethyl-4-methoxy-C 6 H 2 )] 2 ;

L12: formula XII, R 8 is methyl, X 1 is —P[(3,5-dimethyl-4-methyl-C 6 H 2 )] 2 , X 2 is —P[(3,5-di(trifluormethyl)-C 6 H 3 )] 2 ;

L13: formula VIII, R 5 is phenyl and R 6 is dimethylamino, X 1 and X 2 are each —P[(3,5-dimethyl-4-methoxy-C 6 H 2 )] 2 ;

L14: formula XII, R 8 is methyl, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L15: formula X, R 8 is methyl, X 1 is —P(C 6 H 5 ) 2 , X 2 is —P(t-butyl) 2 (S,R-configuration);

L16: formula XII, R 8 is methyl, X 1 is —P(C 6 H 5 ) 2 and X 2 is —P[(3,5-di(trifluoromethyl)-C 6 H 3 )] 2 (S,R-configuration);

L17: formula IX, R 7 is methoxy, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L18: formula X, R 8 is methyl, X 1 is —P(C 6 H 5 ) 2 , X 2 is —P(t-butyl) 3 (R,S-configuration);

L19: formula X, R 8 is methyl, X 1 is —P[(3,5-dimethyl-4-methoxy-C 6 H 2 )] 2 , X 2 is —P[(3,5-di(methyl)-C 6 H 3 )] 2 ;

L20: formula X, R 8 is methyl, X 1 is —P(C 6 H 11 ) 2 , X 2 is —P(t-butyl) 2 ;

L21: formula IX, R 7 is hydroxy, X 1 and X 2 are each —P(C 6 H 5 ) 2 ;

L22: formula XV, R 11 is phenyl, R 12 is 2-methoxy-phen-1-yl;

L23: formula XII, R 8 is methyl, X 1 is —P(4-methoxy-C 6 H 4 ) 2 , X 2 is —P(norbornyl) 2 ;

L24: formula X 1 , R 9 is H, X 1 and X 2 are each —P(i-propyl) 2 ;

L25: formula X, R 8 is methyl, X 1 and X 2 are each —P[(3,5-di(methyl)-C 6 H 3 )] 2 ; and

L26: formula VII, R 3 and R 4 together are —O—CH 2 CH 2 —N(CH 3 ), X 1 and X 2 are each —P(C 6 H 5 ) 2 .

15. A process according to claim 1 , wherein the hydrogenation is effected in the presence of a homogeneous and chiral hydrogenation catalyst comprising:

a [Ru halogenide 2 (diphosphine of formula VII)(chiral diamine)] complex, or

a [Ru halogenide 2 (ligand of formula XIII)(tertiary phosphine)] complex.

16. A process according to claim 15 , wherein the Ru halogenide 2 is formed of Cl, Br or I.

17. A process according to claim 1 , wherein the hydrogenation is effected with an alkali metal trialkyl borohydride or alkali metal aluminium hydride corresponding to one of the formulas XXI and XXIa

alkali metal [B(R 13 ) 3 H]  (XXI),

alkali metal[AI(R 13 ) 3 H]  (XXIa),

where alkali metal represents Li, Na or K, and R 13 is a linear or branched alkyl group containing from 1 to 18 carbon atoms.

18. A process according to claim 17 , wherein R 13 is a linear or branched alkyl group containing from 4 to 12 carbon atoms.

19. A process according to claim 17 , wherein the alkyl is branched in the α position.

20. A process according to claim 17 , wherein R 13 is an alkyl group selected from the group consisting of but-2-yl, pent-2-yl, hex-2-yl, hept-2-yl, oct-2-yl, 2-dimethyl-but-1-yl, 1,2-dimethyl-but-1-yl, 2-ethyl-pent-1-yl, 2-methyl-hex-1-yl, 2-ethyl-hex-1-yl, 1,2,2-trimethyl-eth-1-yl, and 1,2-dimethyl-but-1-yl.