Abstract An efficient two step conversion of Nt-Boc-l-aspartic acid β-benzyl ester to enantiopure 3-(S)-amino-γ-butyrolactone is described. In this route, chemoselective reduction of the α-carboxylic group in the starting material via a mixed anhydride with NaBH 4 afforded the corresponding alcohol in 95% yield without any loss of the optical purity. Subsequent acidic hydrolysis of the N-protected β-amino alcohol not only deprotected the ...