Methylethers from Alcohols and Dimethyl Carbonate

Abstract

Abstract Different synthetic approaches to methylethers by reaction of alcohols with dimethyl carbonate (DMC) have been reported. Direct methylation has been achieved in good yields using basic alumina or hydrotalcite KW2000 as catalyst either in batch or continuous‐flow conditions. A two‐step synthetic approach, consisting of carboxymethylation of the parent alcohol followed by decarboxylation, was also reported. In this case the reaction is complicated by the side reactions occurring and required the use of high temperature and appropriate solvent to achieve methylethers in high yield. A high‐yielding methylation of cyclic sugar isosorbide that incorporates secondary hydroxyls groups, by reaction with DMC, has been also reported. It is noteworthy that methylation of secondary alcohols usually required high temperature and it is complicated by the formation of elimination products; however, in this case, dimethyl isosorbide was achieved at low temperature (90 °C) and in quantitative yield.