Copper-Catalyzed Oxidative Cyclization of Maleimides with Amines and Alkyne Esters: Direct Access to Fully Substituted Dihydropyrroles and Pyrrole Derivatives.

An efficient and practical Cu(I)-catalyzed oxidative cyclization cascade reaction of diverse amines, alkyne esters and maleimides has been developed. The reactions can afford 4,6-dioxopyrrolo[3,4-b]pyrrole-2,3-dicarboxylates and related derivatives with satisfactory yields by altering the reaction conditions slightly. The substrate scope highlights the flexibility of the catalyst, and a reaction mechanism is also proposed.