Triaryl Carbenium Ion Pair Mediated Electrocatalytic Benzylic C−H Oxygenation in Air

The selective oxidation of benzylic C−H bonds is a pivotal transformation in organic synthesis. Undoubtedly, achieving efficient and highly selective aerobic oxidation of methylarenes to benzaldehydes has been highly challenging due to the propensity of benzaldehyde to undergo overoxidation under typical aerobic conditions. Herein, we propose an innovative approach to address this issue by leveraging electrocatalytic processes, facilitated by ion-pair mediators [Ph₃C]⁺[B(C₆F₅)₄]⁻. By harnessing the power of electrochemistry, we successfully demonstrated the effectiveness of our strategy, which enables the selective oxidation of benzylic C−H bonds in benzylic molecules and toluene derivatives. Notably, our approach exhibited high efficiency, excellent selectivity, and compatibility with various functional groups, underscoring the broad applicability of our methodology.