Selective and Efficient Oxidation of Benzyl alcohols to Benzaldehydes by Polydoxirane in the Presence of Molecular Oxygen at Room Temperature

Oxidation of alcohols that lead to the preparation of carbonyl compounds are an importantclass in organic synthesis due to their applications in production of various pharmaceuticaland chemical materials [1]. Various protocols and attempts to oxidation of alcohols (primaryand secondary) in order to form carbonyl compounds show the importance of this basic reactionin organic synthesis [2]. However, there is a continuous demand to develop syntheticmethods for discriminating efficiently various functional groups, because most of the reportedmethods suffer from lack of selectivity, using toxic solvents and oxidant, tedious work-up andharsh condition. In this point of view, chemoselective methods allow the oxidation of primaryalcohols without the exhorting of competitive secondary alcohols. Salicylaldehyde is one ofthe safe, readily available organic compounds in health and reactivity point of view, whichcan be extracted from natural sources such as buckwheat [3]. In this work, we used an efficientand selective method for oxidation of a variety of benzyl alcohols to the correspondingbenzaldehydes in the presence of polydioxirane (PDOX) by molecular oxygen at room temperature(Fig. 1). PDOX was prepared by polycondensation reaction of 5-chloromethyl salicylaldehydefollowed by decoration of dioxirane groups of the framework of PDOX. In ourprevious work we have demonstrated the ability of the PDOX over selective epoxidation ofolefins at room temperature as efficient alternative to dimethyldioxirane.