Copper-catalyzed demethylative esterification of arylmethylketones: a new route for the synthesis of benzocaine

An efficient method for oxidative cleavage of C(CO)–C bonds of ketones has been developed. This procedure enables activated methyl ketones to react with tetraethyl orthosilicate for generation of the corresponding methyl esters using copper as the catalyst. Primary mechanistic studies revealed that in contrary to other related studies, the involvement of the aldehyde as the intermediate of this reaction is highly probable. Interestingly, this study provides an unprecedented positive effect of the elemental sulfur upon this oxidative esterification reaction. As an application of our method, we have reported a two-step procedure for the synthesis of benzocaine. The second step of this procedure involves a highly selective reduction in nitro group in the presence of ester functionality.