Synthesis of chiral spiropyrazoline-β-lactams and spirocyclopropyl-β-lactams from 6-alkylidenepenicillanates
摘要:
Chiral spiropyrazolinepenicillanates were obtained in a stereoselective fashion via 1,3-dipolar cycloaddition reactions of 6-alkylidenepenicillanates with diphenyldiazomethane, phenyldiazomethane, and diazomethane. Microwave-induced ring contraction of spiro-1-pyrazoline-beta-lactams leading to chiral spirocyclopropylpenicillanates is also described. (C) 2014 Elsevier Ltd. All rights reserved.