Metal-assisted synthesis of enantiopure spirocyclic β-lactams from azetidine-2,3-diones

A novel approach to enantiopure spirocyclic β-lactams has been developed by using different intramolecular metal-catalyzed cyclization reactions in monocyclic unsaturated alcohols. The access to cyclization precursors, 2-azetidinone-tethered homoallylic alcohols, (buta-1,3-dien-2-yl)methanols, and α-allenols was achieved by regio and stereoselective addition of stabilized organo-indium reagents to azetidine-2,3-diones in aqueous environment.