C-C and C-O bond formation reactivity of nickel complexes supported by the pyridinophane ^MeN3C ligand

The pyridinophane ligands ^RN3CX (X = H, Br) are well-established scaffolds that facilitate and stabilize nickel oxidative addition complexes to the proximal C(aryl)-X bond. In this study, we report the synthesis, detailed characterization, and reactivity of a series of Ni^II and Ni^III complexes supported by the ^MeN3CX ligand. Our findings demonstrate that Ni^II complexes can be oxidized to readily yield well-defined Ni^III species. Excitingly, the Ni-disolvento complexes exhibit catalytic trifluoroethoxylation to generate the C-O coupled product. In addition, the Ni^III-halide complex undergoes transmetallation with a Grignard reagent and subsequent C-C reductive elimination, while the β-hydride elimination side reaction is suppressed, outperforming its Ni^II analogue.