Synthetic Study of Selective Benzylic Oxidation

Oxidation of bisbenzyl ethers was studied using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). Compared to other benzylic oxidations such as Kornblum type reaction of benzyl bromides or MnO₂ oxidation of benzyl alcohols, DDQ oxidation offered advantages of being mild and highly selective to provide monoaldehyde products. We have explored factors which influence the course of the reaction and exemplified the synthetic value of the approach by preparing a number of aromatic intermediates (7−8, 15−25).