Mechanism of trifl uoromethylation reactions with well-defi ned NHC copper trifl uoromethyl complexes and iodobenzene: A computational exploration

Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene (NHC)-supported CuI trifluoromethyl complexes. Four proposed reaction pathways, namely σ-bond metathesis (BM), concerted oxidative addition-reductive elimination (OARE), iodine atomtransfer (IAT) and single-electron transfer (SET), have been computed by density functional theory (DFT). The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step.