Reduction of Aromatic Aldehydes,Ketones with Acyloxy Substituent at the Ortho-position by NaBH4 in the Presence of Waters

n unusual reduction of some aromatic aldehydes, ketones by sodium borohydride was discovered. In a THF/H₂O or DMSO/H₂O solvent system the aromatic aldehydes, ketones with acyloxy substituent on the ortho-position to the carbonyl group can be reduced to the corresponding alkyl phenols. This unusual reduction is applicable also to the corresponding alcohols of all the above aldehydes, ketones. A putative mechanism was suggested. In addition to the above aldehydes, ketones, benzyl alcohols, certain 4-acyloxybenzyl esters(probably also the 2-substituted analogues) such as 4-benzoyloxybenzyl benzoate was also found to be reduced to methylphenol by this unusual reduction.