ASYMMETRIC SYNTHESIS OF α-AMINO ACIDS BY NONENZYMATIC TRANSAMINATION. VERSATILITY OF THE REACTION AND ENANTIOMERIC EXCESSES OF THE PRODUCTS

Diverse α-keto acids were transformed into the corresponding α-amino acids with enantiomeric excesses ranging from 60 to 96% by the reaction with chiral pyridoxamine analog, (R)- or (S)-15-aminomethyl-14-hydroxy-5,5-dimethyl-2,8-dithia [9] (2,5)pyridinophane (4), and Zn2+ in the molar ratio of 2:1, in methanol. The use of the S enantiomer of 4 gave (R)-α-amino acids, and vice versa.