Patent ID: 8344161

Claim:
A process for the preparation of (3S,4S)- or (3R,4R)-1-benzyl-4-aryl-pyrrolidine-3-carboxylic acids of formula I or salts thereof, wherein X and Y are each independently hydrogen or a halogen atom, with the proviso that at least one of X or Y is a halogen atom, comprising catalytic homogeneous enantioselective hydrogenation of a compound of formula II or salts thereof, wherein X and Y are as above, in the presence of a Ru-catalyst selected from the group consisting of [Ru(OAc) 2 ((R)-2-furyl-MeOBIPHEP)] and [Ru(OAc) 2 ((S)-2-furyl-MeOBIPHEP)].