Asymmetric Transamination of α-Keto Acids Catalyzed by Chiral Pyridoxamines

A new type of novel chiral pyridoxamines 3a–g containing a side chain has been developed. The pyridoxamines displayed catalytic activity and promising enantioselectivity in biomimetic asymmetric transamination of α-keto acids, to give various α-amino acids in 47–90% yields with up to 87% ee's under very mild conditions. An interesting effect of the side chain on enantioselectivity was observed in the reaction.