Acyclic stereoselective boron alkylation reactions for the asymmetric synthesis of beta-substituted alpha-amino acid derivatives.

Optically active syn- or anti-beta-substituted-alpha-amino acid derivatives are prepared in 94 to >/=99% ee and 66-98% ds by reaction of the Schiff base acetate of glycine tert-butyl ester with chiral, nonracemic B-alkyl-9-BBN derivatives in the presence of the Cinchona alkaloid, cinchonidine (CdOH) or cinchonine (CnOH), base, and lithium chloride.