Oxidative Cleavage of Benzylic and Related Ethers, Using an Oxoammonium Salt

Benzylic ethers and related ArCH2OR substrates are oxidatively cleaved by 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) in wet CH3CN at room temperature to give the corresponding aromatic aldehyde and alcohol in high yield. Primary or secondary alcohol products are further oxidized by I to give carboxylic acids and ketones, respectively. The oxidation likely involves a formal hydride abstraction from the benzylic carbon as evidenced by slow reaction of Substrates bearing electron-withdrawing substituents.