Palladium-Catalyzed, Multicomponent Approach to β-Lactams via Aryl Halide Carbonylation

A palladium-catalyzed multicomponent method for the synthesis of beta-lactams from imines, aryl halides, and CO has been developed. This transformation proceeds via two tandem catalytic carbonylation reactions mediated by Pd((PBu3)-Bu-t)(2) and provides a route to prepare these products from five separate reagents. A diverse range of polysubstituted beta-lactams can be generated by systematic variation of the substrates. This methodology can also be extended to the use of iodo-substituted imines to produce novel spirocyclic beta-lactams in good yields and selectivity.