Water-enhanced electrochemical hydrogenolysis of aryl C-O bonds

Phenolic compounds are naturally abundant and easily derived, yet the cleavage of aryl C-O bonds typically relies on specific methods, especially those involving transition metal catalysts. In this study, we present a user-friendly and sustainable electrochemical approach for aryl C-O bond cleavage and hydrogenation. Salient features of this method include the use of an undivided cell, inexpensive dimethylformamide as a hydrogen source, a broad substrate scope, and practical derivatizations. A key factor in the success of this approach is the addition of water, which acts as a decomposing agent for the iminium intermediate, potentially competing with the substrate in cathodic reduction. Mechanistic studies elucidate the reaction cycle, with particular emphasis on the one-electron reduction process and the role of bromide.