Diastereoselective and enantioselective heterogeneous catalytic hydrogenation of aminocinnamic acid derivatives

Various kinds of aminocinnamic acid derivatives were hydrogenated with diff erent stereoselectivities. In the presence of cinchonidine or(-)-dihydroapo vincaminic acid ethyl ester modifiers, the enantioselective hydrogenations resulted in very low enantiomeric excesses tee). Moderate diastereomeric ex cesses (de, 5-68%) were achieved in the diastereoselective hydrogenations. The highest de (68%) was obtained in the hydrogenation of N-acetyldehydroph enylalanyl-(S)-prolinanilide due to a 10-member intermediate stabilized by hydrogen bond. (C) 1999 Elsevier Science B.V. All rights reserved.