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 (ArCl3), 3,5-(CF3)2C6H3 (ArF6), or 2-py) with the copper­(II) t-butoxide complex [Cl2NN]­Cu-tOBu yields the corresponding copper­(II) anilides [Cl2NN]­Cu-NHAr. X-ray diffraction of these species reveal three different bonding modes for the anilido moiety: κ1-N in the trigonal [Cl2NN]­Cu-NHArCl3 to dinuclear bridging in {[Cl2NN]­Cu}2(μ-NHArF6)2 and κ2-N,N in the square planar [Cl2NN]­Cu­(κ2-NH-2-py). Magnetic data reveal a weak antiferromagnetic interaction through a π-stacking arrangement of [Cl2NN]­Cu-NHArCl3; 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 tBuOOtBu is used, which allows for HAA of R-H to occur from the tBuO• radical generated by reaction of [Cl2NN]Cu and tBuOOtBu. The principal role of these copper­(II) anilides [Cl2NN]­Cu-NHAr is to capture the radical R• generated from HAA by tBuO• to give functionalized aniline R-NHAr, resulting in a novel amino variant of the Kharasch–Sosnovsky reaction.