摘要 |
The invention relates to the preparation of enantiomerically pure (S)-1,1,1-trifluoro-2- propanol by an asymmetric hydrogenation of 1,1,1-trifluoroacetone which process comprises hydrogenating 1,1,1-trifluoroacetone in the presence of a ruthenium phosphine complex represented by formula Ru(E)(E')(L)(A) wherein E, E' are both chloro or E is hydrogen and E' is BH4; L is a chiral diphosphine ligand; and A is an optionally chiral diamine comprising the variants a) in the presence of a weak base and with or without an additive in case when E and E' are both chloro or b) in the absence of a base and an additive in case when E and E' are hydrogen and BH4. |