Electrocatalytic C–H phosphorylation through nickel(III/IV/II) catalysis

Abstract

<h2>Summary</h2> C–H phosphorylation was achieved by Earth-abundant nickel catalysts with waste-free electricity as the redox surrogate. The robust nickela-electrooxidative C–H activation of arenes, heteroarenes, and olefins with diverse phosphonating reagents successfully delivered arylphosphonates, phenylphosphine oxides, and diazaphospholidine oxides of relevance to bioactive compounds and materials. The guanidine-assisted electrooxidative C–P formation avoided chemical oxidants with molecular hydrogen as the sole byproduct. Catalytically relevant nickel(II) and nickel(III) intermediates were isolated and fully characterized by X-ray diffraction analysis. Catalytically relevant nickel complexes were observed by <i>in operando</i> high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) monitoring. Cyclic voltammetry analysis and density functional theory (DFT) calculations provided strong evidence for a nickel(III/IV/II) manifold.