Patent ID: 7183443

Claim:
A process for the preparation of an enantiomerically enriched compound of formula 1 or a salt thereof, wherein: C* represents an asymmetric carbon atom; R 1 and R 2 are different from each other, and, each independently, represents H, a substituted or unsubstituted alkyl or aryl group; R 3 represents CH 2 OH or an optionally protected CHO group; R 5 represents H, a substituted or unsubstituted alkyl or aryl group; and R 4 represents H or C(═O)R 6 wherein R 6 represents H, a substituted or unsubstituted alkyl, aryl or alkoxy group, or R 4 represents or an amine protecting group, or R 4 and R 5 form together with the N to which they are attached a cyclic imide group, which process comprises hydrogenating an enantiomerically enriched compound of formula 2 or a salt thereof, wherein C*, R 1 , R 2 , and R 5 are as defined above; and R 7 represents H or C(═O)R 6 wherein R 6 is as defined above, or R 7 represents an amine protecting group, or R 5 and R 7 form together with the N to which they are attached a cyclic imide group, in the presence of an aqueous solvent, hydrogen, a hydrogenation catalyst and a mineral acid.