UNUSUAL AMINO-ACIDS .6. SUBSTITUTED ARYLAMINO ACIDS BY ASYMMETRIC HYDROGENATION OF N-CBZ AND N-BOC PROTECTED DEHYDROAMINO ACID-DERIVATIVES

Substituted N-Cbz and N-Boc protected arylamino acrylic acids and este rs have been prepared and used in asymmetric hydrogenations catalyzed by PROPRAPHOS-Rh. Stereoselectivities > 90% ee could be achieved, the rate of which is dependent on the position of the substituent in the a romatic ring, The N-Boc derivatives provide advantages compared with t he N-Cbz analogues. The amino acid derivatives were fully characterize d by F-19, C-13, and H-1 NMR spectroscopy. (C) 1996 Wiley-Liss, Inc.