Electrochemical Cleavage of Aryl Ethers Promoted by Sodium Borohydride

The NaBH4 (or TBABH(4))-promoted electrochemically reductive cleavage of aryl CO bonds in diaryl ethers to produce phenols and arenes with high yields and excellent selectivities at room temperature was reported. Air- and water-tolerable, this process also works on the cleavage of aryl alkyl and benzyl ethers. The application to break the beta-O-4, alpha-O-4, and 4-O-5 lignin model compounds is also illustrated, which highlights the advance toward the goal of lignin conversion.