Copper‐Catalyzed Remote C(sp3)–H Trifluoromethylation of Carboxamides and Sulfonamides

We report herein an unprecedented protocol for trifluoromethylation of unactivated aliphatic C(sp3)–H bonds. With Cu(OTf)2 as the catalyst, the reaction of N‐fluoro‐substituted carboxamides (or sulfonamides) with Zn(CF3)2 complexes provides the corresponding δ‐trifluoromethylated carboxamides (or sulfonamides) in satisfactory yields under mild conditions. A radical mechanism involving 1,5‐hydrogen atom transfer of N‐radicals followed by CF3‐transfer from Cu(II)–CF3 complexes to the thus formed alkyl radicals is proposed.

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