A DIRECT PREPARATION OF ACETYL-(S)-PHENYLALANYL-(S)-PHENYLALANINE METHYL ESTER BY A DOUBLE ASYMMETRIC HYDROGENATION

Acetyl-(S)-phenylalanyl-(S)-phenylalamine methyl ester [Ac(S)Phe(S)PheOMe] is obtained with high diastereoselectivity and enantioselectivity by catalytic hydrogenation, using [Rh(dipamp)(cod)]+BF–4(dipamp =R,R-1,2-bis[(2-Methoxypheny) phenylphosphino] ethane, cod = cyclo-octa-1,5-diene) as chiral catalyst, of a substrate containing two prochiral doubly bonded carbon atoms, which is easily available from glycine and benzaldehyde.