Copper-catalyzed endo-type trifluoromethylarylation of alkynes

A new copper-catalyzed trifluoromethylarylation reaction of alkynes has been developed. The transformation represents the first example of endo-type carbotrifluoromethylation of unsaturated carbon-carbon bonds and provides efficient access to a variety of CF3-substituted dihydronaphthalenes and chromenes.