Augmentation of Pd-catalysed oxidative C–H/C–H carbonylation through alternating current electrosynthesis†

In light of the burgeoning biological applications associated with xanthones, the development of highly efficient synthetic methodologies for their production has emerged as a pivotal objective of chemical research. Amidst the array of available protocols, the oxidative carbonylation of diaryl ethers with carbon monoxide (CO) stands out as a notably uncomplicated route, often necessitating stoichiometric oxidants. Herein, we present a feasible approach employing unsymmetrical-waveform alternating current (AC) electrolysis to facilitate Pd-catalysed oxidative C–H/C–H carbonylation. Leveraging a straightforward catalytic system, we demonstrate the conversion of diverse diaryl ethers into xanthones with moderate to commendable yields. Our mechanistic investigations illuminate the indispensable role played by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in the electrochemical system, particularly its ability to recycle heterogeneous palladium species within the solution.