Efficient benzoins-to-benzils oxidation under air with reduced iron powder additive

The oxidation of benzoins to benzils typically proceeds through a radical pathway, which, however, frequently leads to over-oxidation and reduced product yields. To suppress this side reaction, reduced iron powder was introduced into the oxidative system, which operates under simple and efficient conditions using air as the oxidant in alkaline aqueous media at room temperature. The iron functions by interacting with and removing the hydroperoxide anions responsible for over-oxidation. Our results demonstrate that both Fe(II) and Fe(III) serve as effective additives for this purpose. This iron-mediated approach thus provides a practical and efficient strategy for the aerobic oxidation of benzoins and related aromatic compounds under mild conditions.