Photoelectrocatalytic allylic C–H oxidation to allylic alcohols coupled with hydrogen evolution

Abstract

Allylic C–H bond oxidation of cycloolefins to allylic alcohols has attracted tremendous attention owing to its widespread application in pharmaceuticals production and natural synthesis. However, the production of allylic alcohols still suffers from the challenges of unsatisfactory selectivity and harsh conditions. Herein, we report the sustainable photoelectrocatalytic (PEC) allylic C–H oxidation to allylic alcohols, achieving the oxidation of cyclohexene to 2-cyclohexenol with a selectivity of 97.2 %. We reveal the reaction pathway wherein photogenerated holes and OH synergistically activate cyclohexene to carbocation intermediates, and these intermediates combine with OH to produce 2-cyclohexenol. Additionally, the mechanism by enriching OH in local area of photoanode surface to enhance PEC performance is uncovered. Furthermore, we designed a self-powered PEC reaction system, attaining a 2-cyclohexenol productivity of 11.95 μmol h (selectivity > 97 %) coupled with a H productivity of 1.44 mL h, demonstrating the application potential of this new strategy.