Alkoxy Radical-Mediated Alkene Difunctionalization via Electrophotochemical LMCT Catalysis for the Synthesis of Functionalized Ethers

Abstract Alkoxy radical-mediated hydroetherification offers an atom-economical approach for C–O bond construction. However, the difunctionalization of alkenes driven by alkoxy radicals remains elusive due to the inherent challenges associated with the generation and controlled reactivity of these reactive oxygen-centered radicals. Here we report a homogeneous molecular electrophotochemical LMCT catalysis strategy that enables the difunctionalization of enol derivatives, achieving efficient alkenyletherification to access a diverse array of functionalized ethers. This method features mild conditions, broad substrate scope encompassing both electron-rich and electron-deficient alkenes, and effective suppression of direct alkene oxidation side reactions. Detailed mechanistic studies reveal that a visible-light-induced ligand-to-metal charge transfer (LMCT) process selectively activates the alcohol hydroxyl group, generating a highly electrophilic alkoxy radical in situ to initiate the anti-Markovnikov intramolecular addition to the alkene. Subsequent electrochemical oxidation precisely dictates the fate of the resulting carbon-centered radical, enabling the introduction of an alkenyl group, respectively, to ultimately yield the target products.