Oxidation of phenols, pyrocatechols, and hydroquinones to ortho-quinones using benzeneseleninic anhydride

Benzeneseleninic anhydride has been used as a mild oxidising reagent to convert phenols into o-quinones including some examples where the p-position is unblocked. The method is limited to the production of o-quinones which are not susceptible to further reaction. Pyrocatechols and hydroquinones can also be oxidised to the corresponding quinones in excellent yield using benzeneseleninic anhydride.