A Facile Access to 2-exo-Methylenepenam A Potent Intermediate for Syntheses of New b-Lactamase Inhibitors

Tanaka, H.; Kameyama, Y.; Yamauchi, T.; Torii, S. J. Chem. Soc., Chem. Commun. 1992, 1793.

A convinient synthesis of 2-exo-methylenepenams was performed by reductive cyclization of allenecarboxylates in a MX_n/M' bimetal redox system and subsequent manipulation of the 2-exo-methylene moiety of opened new entries to b-lactam antibiotics and b-Lactamase inhibitors.