Deoxygenative Functionalization of Unprotected Phenols by Linear Paired Electrolysis

Phenols are abundant aromatic feedstocks widely used in organic synthesis and are commonly obtained from lignin and other renewable resources. However, the functionalization of their inert C(sp²)─OH bonds remains a formidable challenge, often necessitating additional preactivation steps or harsh reaction conditions. Here, we report an electrochemical strategy that enables the cleavage of phenolic C(sp²)─OH bonds in a formally direct manner under mild and sustainable conditions through a linear paired electrolysis, allowing both hydrodeoxygenation and, for the first time, deoxygenative alkylation with alkenes. This method is compatible with a range of functional groups and complex molecular architectures, including natural product-derived and biomass-derived phenols, providing a general and sustainable platform for phenol valorization without requiring additional operations to convert the substrates into their protected derivatives. Mechanistic investigations reveal that an amino phosphine with low oxidation potential and water are essential to the success of this strategy, enabling the in situ formation of a key phosphinate intermediate that subsequently undergoes reduction at the cathode, either directly or mediated by 2-methylbenzonitrile (M4) to drive the overall transformation.