Generation of Penems, Carbapenems and Aza Analogs of Cephems by the Addition of Heterocycles and Other Building Blocks to Azetinones

Addition of nucleophiles including heterocycles and precursors of vicinal tricarbonyls to azetinones generates building blocks incorporating potential electrophilic centers. Oxidation of these products provides reactive carbonyl units suitably located for reaction with the β-lactam NH yielding bicyclic products of biological interest.