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-^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-NHAr^Cl3 to dinuclear bridging in {[Cl₂NN]­Cu}₂(μ-NHAr^F6)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-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 ^tBuOO^tBu is used, which allows for HAA of R-H to occur from the ^tBuO^• radical generated by reaction of [Cl₂NN]Cu and ^tBuOO^tBu. 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.