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

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.