Copper-Catalyzed Intramolecular Carbotrifluoromethylation of Alkynes for the Construction of Trifluoromethylated Heterocycles

A mild and efficient copper-catalyzed intramolecular carbotrifluoromethylation of alkynes has been achieved in the presence of Togni reagent as trifluoromethylating reagent. The reaction tolerates a range of substrates to give a group of trifluoromethylated heterocycles with high selectivities. A plausible mechanism was proposed on the basis of experimental results.