Cleavage Of C(Sp(3))-F Bonds In Trifluoromethylarenes Using A Bis(Nhc)Nickel(0) Complex

The first example of the oxidative addition of a C(sp(3))-F bond in trifluoromethylarenes to a nickel(0) complex is described. A nickel(0) complex that bears two N-heterocyclic carbene (NHC) ligands of low steric demand is able to cleave C(sp(3))-F bonds of trifluoromethylarenes to afford the corresponding trans-difluorobenzyl nickel(H) fluoride complexes. Isolation and characterization studies suggested that the cleavage of the C(sp(3))-F bond proceeds via an eta(2)-arene nickel(0) complex. Taking advantage of the reactivity of these nickel(II) fluoride complexes, we developed a catalytic hydrodefluorination of trifluoromethylarenes using hydrosilanes. A computational study indicated that the electron-rich nickel(0) center supported by two relatively small NHC ligands cleaves the C(sp(3))-F bond via a syn S(N)2' mechanism.