Recent advances in electrochemically driven deoxygenation/deoxygenative coupling of C−O and C=O bonds

Alcohols, aldehydes and ketones, which contain oxygen-containing functional groups such as C−O and C=O, are widely present in drugs, fine chemicals, and biomass. These compounds provide diverse carbon skeletons for organic transformations via deoxygenation or deoxygenative coupling, and are crucial to the synthesis and late-stage modification of drugs and natural products. However, the high bond dissociation energies (BDEs) of C−O and C=O bonds pose a significant challenge to their activation and cleavage. Traditional methods, although effective, have drawbacks such as the need for stoichiometric activating reagents, harsh reaction conditions, the use of toxic reagents, substantial waste generation, and laborious operations. Recently, the rapid development of reductive electrochemistry has provided an effective alternative to conventional reduction reactions by utilizing electrons as reductants. Cathodic electroreduction has enabled green and sustainable deoxygenation and deoxygenative coupling of C−O and C=O bonds, and has thus opened new synthetic routes in this area. This review summarizes the latest progress in this field, with emphasis on reaction strategies, synthetic applications, and mechanisms, and discusses future directions. This review introduces both direct and indirect methods for the activation and transformation of C−O or C=O bonds through reductive electrochemistry in recent years, details the practical applications and elucidates the reaction mechanisms of these strategies.