Stereochemical Studies. LIX.1) Asymmetric Transamination from (S)-α-Amino Acids. Synthesis of optically Active Amines by Chemical Transamination of (S)-α-Amino Acid Esters to Ketones

Abstract

Asymmetric synthesis of optically active amines (15) by catalytic hydrogenation and chemical transamination of the Schiff bases (10) of (S)-α-amino acid esters (8) with ketones (9) was achieved. The effects of solvents and the ester moiety of chiral reagents on the asymmetric induction were examined, and (S)-(+)-2-amino-3-phenylpropane (15a) was prepared from (S)-valine tert-butyl ester and phenylacetone in 63% yield and 87% optical yield. The possible steric course of the asymmetric hydrogenation is discussed. The reduction of the Schiff bases (10) with sodium borohydride is also described. © 1983, The Pharmaceutical Society of Japan. All rights reserved.