Synthesis of cis-Substituted β-Lactams, Potential Intermediates for cis-Carbapenems, from L-Aspartic Acid

Abstract

(3S)-3-Benzyloxycarbonylamino-γ-butyrolactone was prepared by the regioselective reduction of L-aspartic acid. Alkylation and aldol condensation of the γ-butyrolactone afforded the trans isomer selectively. The resulting 2, 3-trans γ-butyrolactone was hydrolyzed and then cyclized to give the 3, 4-cis β-lactam. By taking advantage of this strategy, key intermediates of epi-PS-5 and carpetimycins were synthesized.