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

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 in operando 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. [Display omitted] •Electro-oxidative C–H phosphorylation of arenes and alkenes•Chemical oxidants are not required in an undivided cell setup•Sustainable 3d nickela-electrocatalysis with H2 as the only byproduct•Mechanistic insights by NMR spectroscopy, X-ray analysis, mass spectrometry, and CV Phosphorus-containing molecules play a pivotal role in numerous applied areas and have transformative applications in molecular syntheses and medicinal chemistry, as well as in crop-protection agents and pharmaceutical industries. As a consequence, there is continued strong demand for resource-economical strategies for their assembly. Although direct methods for C–H/C–P functionalizations are particularly attractive, thus far they have largely relied on precious-transition-metal catalysts and toxic or expensive chemical oxidants, jeopardizing the overall molecular efficiency. In sharp contrast, we herein disclose a sustainable strategy for resource-efficient access to a plethora of aryl and alkenyl phosphonates and phosphines by means of electro-oxidative 3d nickela-electrocatalysis. Key to our success were detailed spectroscopic and computational mechanistic insights into a nickel(III/IV) manifold through oxidation-induced reductive elimination. A resource-economical strategy for accessing a wealth of biorelevant aryl and alkenyl phosphorus compounds was accomplished by sustainable nickela-electrocatalysis by C–H/P–H functionalizations. The scalable electrocatalysis proved viable in a user-friendly undivided cell setup and prevents toxic or expens