A direct preparation of acetyl-(S)-phenylalanyl-(S)-phenylalanine methyl ester by a double asymmetric hydrogenation

Abstract

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.