Copper-catalyzed tandem trifluoromethylation/cyclization of internal alkynes

Copper-catalyzed tandem trifluoromethylation/cyclization of internal alkynes with Umemoto's reagent leads to 3-trifluoromethyl-1,2-dihydronaphthalene derivatives in moderate to good yields. The utility of this copper-catalyzed tandem reaction was demonstrated by oxidizing and reducing the trifluoromethylated product to give naphthalene and tetrahydronaphthalene, respectively, and the development of a short route to a trifluoromethylated analogue of Nafoxidine.