Copper-Mediated Cyclization of Terminal Alkynes with CF 3 -Imidoyl Sulfoxonium Ylides To Construct 5-Trifluoromethylpyrroles.

A copper-mediated [3 + 2] cyclization of CF 3 -imidoyl sulfoxonium ylides and terminal alkynes has been demonstrated. This work provides a practical approach for assembling 5-trifluoromethylpyrroles with the merits of a broad substrate scope, good functional tolerance, and mild reaction conditions. Control experiments and DFT studies indicate that this reaction may involve the addition of π-bonds of terminal alkynes by copper-carbene radicals and hydrogen migration.