Harnessing Electrochemical Proton-Coupled Electron Transfer for Radical Generation from Diazo Compounds

Abstract

Although diazo compounds are privileged reagents in organic synthesis, sustainable methods for their radical engagement remain scarce, with most existing protocols relying on costly photocatalysts or stoichiometric reductants. Herein, we report an electrochemical proton-coupled electron transfer (PCET) strategy for the reductive activation of diazo compounds, granting access to electrophilic radicals in the absence of transition metals and exogenous reductants. This versatile platform enables diverse transformations, including hydroalkylation of alkenes, carboxylation with CO2, and multicomponent Miniscitype alkylations, all of which exhibit high efficiency and broad functional group tolerance. Mechanistic investigations support a paired electrolysis scenario wherein the anodic oxidation of methanol serves as the proton source to facilitate the cathodic activation of diazo compounds via PCET. This sustainable protocol broadens the synthetic repertoire of diazo compounds and represents a significant advancement in green electrochemical synthesis.