Copper-Catalyzed Direct Cycloaddition of Imidazoles and Alkenes to Trifluoromethylated Tricyclic Imidazoles.

We reported herein a copper-catalyzed trifluoromethylarylated cycloaddition of imidazoles and olefins using CF3SO2Cl as the radical source to synthesize highly functionalized tricyclic imidazoles. This procedure exhibits a wide range of substrate scope with 25%-93% isolated yields (36 examples). Mechanistic studies were carried out to support a free trifluoromethyl radical pathway.