Ester groups are among the most important and abundant functional groups in chemistry and are used in medicine, biology, chemistry, industry, fine chemicals, natural products, and poly- mers.1 The traditional esterification method is accessed by a two-step procedure that involves the stoichiometric activation of a carboxylic acid as an anhydride, acyl halide or activated ester fol- lowed by subsequent nucleophilic substitution with alcohols.2 Aldehydes are bulk scale raw chemicals in industry and esterification of readily available aldehydes with alcohols is an attractive alternative. Indeed, it is often required direct conversion of alde- hydes or alcohols into esters during various stages in the synthesis of different natural products.3 Several reagents and catalysts such as iodine and sodium nitrite, bis(pyridine)iodoniumtetrafluoroborate,N-bromosuccinimide-pyridine, methyltrioxorhenium– H2O2, Cu(ClO4)2–InBr3– TBHP, and CuF2–TBHP have been reported for the direct oxidative esterification of aldehydes.4 In this work, we wish to report using of urea-aceton peroxide/bromine system for one-pot oxidative esterifivation of aldehydes in mild conditions (Scheme 1).
