Total synthesis of β-lactamase inhibitors related to clavulanic acid

Abstract

(E)-3-Methoxycarbonylmethylene-7-oxo-4-oxa-1-azabicyclo[3.2.0]heptane (6), its geometric isomer (7), and a related vinyl chloride (8) have been obtained by a three-step synthesis from 4-methylthioazetidin-2-one.