Copper(II) anilides in sp³ C-H amination.

We report a series of novel β-diketiminato copper(II) anilides [Cl2NN]Cu-NHAr that participate in C-H amination. Reaction of H2NAr (Ar = 2,4,6-Cl3C6H2 (Ar(Cl3)), 3,5-(CF3)2C6H3 (Ar(F6)), or 2-py) with the copper(II) t-butoxide complex [Cl2NN]Cu-(t)OBu yields the corresponding copper(II) anilides [Cl2NN]Cu-NHAr. X-ray diffraction of these species reveal three different bonding modes for the anilido moiety: κ(1)-N in the trigonal [Cl2NN]Cu-NHAr(Cl3) to dinuclear bridging in {[Cl2NN]Cu}2(μ-NHAr(F6))2 and κ(2)-N,N in the square planar [Cl2NN]Cu(κ(2)-NH-2-py). Magnetic data reveal a weak antiferromagnetic interaction through a π-stacking arrangement of [Cl2NN]Cu-NHAr(Cl3); solution EPR data are consistent with monomeric species. Reaction of [Cl2NN]Cu-NHAr with hydrocarbons R-H (R-H = ethylbenzene and cyclohexane) reveals inefficient stoichiometric C-H amination with these copper(II) anilides. More rapid C-H amination takes place, however, when (t)BuOO(t)Bu is used, which allows for HAA of R-H to occur from the (t)BuO(•) radical generated by reaction of [Cl2NN]Cu and (t)BuOO(t)Bu. The principal role of these copper(II) anilides [Cl2NN]Cu-NHAr is to capture the radical R(•) generated from HAA by (t)BuO(•) to give functionalized aniline R-NHAr, resulting in a novel amino variant of the Kharasch-Sosnovsky reaction.