The Enantioselective Synthesis of α-Amino Acid Derivatives via Organoboranes

Abstract
Optically active (S)-α-amino acids are prepared in 54−95% ee (12 cases) by reaction of the Schiff base acetate of glycine tert-butyl ester with B-alkyl-9-BBN derivatives in the presence of the Cinchona alkaloid, cinchonidine, and base. The enantiomeric (R)-α-amino acids are available in 59−92% ee (3 cases) by using cinchonine as the chiral control element.