Copper-Catalyzed Remote C(sp 3 )−H Trifluoromethylation of Carboxamides and Sulfonamides

Abstract

Reported herein is an unprecedented protocol for trifluoromethylation of unactivated aliphatic C(sp 3 )−H bonds. With Cu(OTf) 2 as the catalyst, the reaction of N-fluoro-substituted carboxamides (or sulfonamides) with Zn(CF 3 ) 2 complexes provides the corresponding δ-trifluoromethylated carboxamides (or sulfonamides) in satisfactory yields under mild reaction conditions. A radical mechanism involving 1,5-hydrogen atom transfer of N-radicals followed by CF 3 -transfer from Cu II −CF 3 complexes to the thus formed alkyl radicals is proposed.