Ruthenium-Catalyzed [3 + 2] Cycloaddition of 2H-Azirines with Alkynes: Access to Polysubstituted Pyrroles.

A ruthenium-catalyzed intermolecular [3 + 2] cycloaddition of 2H-azirines and activated alkynes is reported, which provides polysubstituted pyrroles in moderate to good yields. This approach features a C-N bond cleavage of 2H-azirines by a ruthenium catalyst. The results of this study would provide a complementary method to synthesize polysubstituted pyrroles from the known 2H-azirine approaches and advance 2H-azirine chemistry.