| abstract |
The present invention relates to a process for the preparation of an optically active carbonyl compound by asymmetric hydrogenation of a prochiral α,β-unsaturated carbonyl compound with hydrogen in the presence of at least one optically active transition metal catalyst that is soluble in the reaction mixture and which has rhodium as catalytically active transition metal and a chiral, bidentate bisphosphine ligand, wherein the reaction mixture during the hydrogenation of the prochiral α,β-unsaturated carbonyl compound additionally comprises at least one compound of the general formula (I): n n n n n n n n n n in which n R 1 , R 2 : are identical or different and are C 6 - to C 10 -aryl which is unsubstituted or carries one or more, e.g. 1, 2, 3, 4 or 5, substituents which are selected from C 1 - to C 6 -alkyl, C 3 - to C 6 -cycloalkyl, C 6 - to C 10 -aryl, C 1 - to C 6 -alkoxy and amino; n Z is a group CHR 3 R 4 or aryl which is unsubstituted or carries one or more, e.g. 1, 2, 3, 4 or 5, substituents which are selected from C 1 - to C 6 -alkyl, C 3 - to C 6 -cycloalkyl, C 6 - to C 10 -aryl, C 1 - to C 6 -alkoxy and amino, wherein R 3 and R 4 are as defined in the claims and the description. |