Copper-Catalyzed Synthesis of Polysubstituted Pyrroles through [3+1+1] Cycloaddition Reaction of Nitrones and Isocyanides.

An efficient, copper-catalyzed [3+1+1] cycloaddition reaction was developed for the expedient synthesis of pharmacologically interesting polysubstituted pyrroles from easily available nitrones and α-acidic isocyanides. The given approach features a new mode of cycloaddition between nitrones and isocyanides with wide substrate scope, good functional group tolerance, and operational simplicity. The operando infrared spectroscopy was used for the characterization of reaction intermediates.