Stereoselective synthesis and functionalization of N-alkyl-beta-lactams

Novel polyfunctionalized N-alkyl-beta-lactams were prepared with high stereoselectivity in an efficient manner by a palladium-catalyzed [2+2] carbonylative cycloaddition of allyl bromide with heteroarylidene N-alkyl-amines The type of alkyl group linked to the nitrogen atom influences the reaction stereoselectivity. Moreover, the C-3 and the C-4 positions of the azetidinone ring can be further stereoselectively functionalized inserting various groups through the generation of a stable azetidinyl carbanion and then captured by various electrophiles.