Silver-Catalyzed [3 + 2] Annulation of 2H-Azirines and CF₃-Imidoyl Sulfoxonium Ylides: Access to CF₃-Substituted 1H- and 2H-Pyrroles

A novel silver-catalyzed [3 + 2] annulation reaction between 2H-azirines and CF3-imidoyl sulfoxonium ylides has been developed, enabling the synthesis of CF3-substituted pyrrole derivatives. In this transformation, the CF3-imidoyl sulfoxonium ylides are first employed as a C2 synthon to synthesize CF3-1H- and 2H-pyrroles. This reaction features a broad substrate scope and generates dimethyl sulfoxide as a byproduct. Moreover, the CF3-pyrrole derivatives could be synthesized on a gram scale, and a possible catalytic cycle was proposed.