Acid/halide co-mediated transesterification of unactivated carboxylic esters with O–H nucleophiles

The transesterification of unactivated carboxylic esters with alcohols was achieved in one pot through acid/halide cooperative catalysis. By this strategy, various weakly nucleophilic phenols could react with unactivated methyl esters to produce the corresponding phenolic esters in good to high yields. Aliphatic alcohols could also be used as the nucleophiles and showed higher reactivity. Moreover, high functional group tolerance has been demonstrated. This reaction is also applicable to the late-stage modification of clinical drug derivatives. These results clearly show the potential synthetic value of this new reaction in organic synthesis.