Electrochemical reduction of benzoic acid esters using water as a H/D source

Abstract

Arguably, water is an ideal hydrogen source for reduction reactions, however with significant difficulties in practice. In this work, water was utilized as a hydrogen source for the electrochemical reduction of benzoic acid esters in an undivided cell by electrolysis with either direct current or rapid alternating polarity current, depending on the electronic properties of the ester. Notably, reactions using D₂O afforded valuable d₂-benzyl alcohols, with D incorporation rates as high as 97%. Mechanistic studies revealed that the reaction pathway depended on the substrate.