C–C and C–O Bond Formation Reactivity of Nickel Complexes Supported by the Pyridinophane MeN3C Ligand

Abstract

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 NiIII-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.