Patent ID: 7504544

Claim:
A method for preparing an enantiomerically pure (S)-1,1,1-trifluoro-2-propanol by an asymmetric hydrogenation of 1,1,1-trifluoroacetone comprising hydrogenating 1,1,1-trifluoroacetone in the presence of a ruthenium phosphine complex catalyst represented by formula Ru(E)(E′)(L)(A) wherein E, E′ are both chloro or E is hydrogen and E′ is BH 4 ; L is a chiral diphosphine ligand; and A is an optionally chiral diamine wherein hydrogenation occurs in the absence of a solvent and a) in the presence of a weak base, with or without an additive, when E and E′ are both chloro or b) in the absence of a base and an additive when E and E′ are hydrogen and BH 4 .