Cu(I)-Catalyzed Three-Component Coupling of Trifluoromethyl KetoneN-Tosylhydrazones, Alkynes and Azides: Synthesis of Difluoromethylene Substituted 1,2,3-Triazoles

A CuI-catalyzed three-component coupling of trifluoromethyl ketone N-tosylhydrazones, alkynes and azides has been developed. The reactionrepresents a straightforward method to access difluoromethylene substituted 1,2,3-triazoles. Mechanistically, it has been proposed that the reaction follows a pathway involving the formation of Cu(I)triazolide intermediate, Cu(I) carbene formation, migratory insertion, and β-fluoride elimination. Thetransformation is featured by mild conditions, wide substrate scope and high efficiency.