Copper-Catalyzed Trifluoromethylation-Cyclization of Enynes: Highly Regioselective Construction of Trifluoromethylated Carbocycles and Heterocycles

Regioselective trifluoromethylation-cyclization: A method for copper-catalyzed trifluoromethylation-cyclization of simple enynes using the C-C triple bond as a nucleophile is reported for the first time (see scheme). The reaction proceeds efficiently in a highly regioselective manner to give various 5- or 6-exo-dig carbocycles and heterocycles in moderate to high yields.