Copper-Catalyzed Trifluoromethylselenolation of Aryl and Alkyl Halides: The Silver Effect in Transmetalation

A catalytic trifluoromethylselenolation of aryl and alkyl halides by a Cu­(I) catalyst has been developed. A key intermediate, [(phen)­Cu­(SeCF3)]2 (5) was successfully isolated and characterized by X-ray diffraction. The important role of silver in the transmetalation process during the catalytic cycle was elucidated. A wide range of trifluoromethylselanes have been prepared from readily available starting materials from a method that tolerates various important functional groups.