Copper-Catalyzed Ring-Opening Radical Trifluoromethylation of Cycloalkanone Oximes.

The copper-catalyzed ring-opening C-trifluoromethylation of cycloalkanone oximes with Zn(CF3)2 complexes is described. The reaction proceeds in dichloromethane under mild conditions, providing an efficient and general entry to γ- or δ-CF3-substituted nitriles via tandem N-O and C(sp2)-C(sp3) bond cleavage and C(sp3)-CF3 bond formation. The protocol exhibits a broad substrate scope and wide functional group compatibility. A radical mechanism involving the CF3 transfer from Cu(II)-CF3 complexes to alkyl radicals is proposed.