Symmetric esters are important compounds in the flavor and fragrance industries and have also found application in pharmaceutical and cosmetic preparations. The oxidative esterification of primary alcohols has proven to be an attractive route to such esters. Many strategies based on metal-containing as well as metal-free reagents for the conversion have been developed. Recent work in the area of non-metal oxidative esterification has focused on 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and its derivatives for the conversion of alcohols and aldehydes to symmetric esters, however complicating factors have been the requirement for stoichiometric reagents or anhydrous conditions.<br/>Here, we show that TEMPO/CaCl<sub>2</sub>/Oxone form a convenient catalytic system for the synthesis of the aforementioned symmetric esters from primary alcohols in a biphasic dichloromethane-water solvent mixture. The substrate scope of the reaction method with regards to its functional group tolerance will be discussed. In addition, the application of the method to diols and sugar-derivatives will be reported.

Phase-transfer-catalyzed oxidative esterification of primary alcohols by TEMPO

251st National Meeting (2016)

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