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

A palladium-catalyzed multicomponent method for the synthesis of β-lactams from imines, aryl halides, and CO has been developed. This transformation proceeds via two tandem catalytic carbonylation reactions mediated by Pd­(P^tBu₃)₂ and provides a route to prepare these products from five separate reagents. A diverse range of polysubstituted β-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 β-lactams in good yields and selectivity.