The addition reaction of dialkyl carbonates to ketones

the reaction of benzyl phenyl ketone with dimethyl carbonate gives methyl benzoate and methyl phenyl acetate; diethyl carbonate gives the corresponding ethyl esters. The reaction takes place at high temperature (about 200 °C) and in the presence of potassium carbonate as a catalyst. Other benzyl ketones react similarly. Aliphatic ketones yield a less selective addition. Accordingly, cyclohexanone with dimtheyl carbonate gives dimethyl pimelate. The reaction is a retroClaisen condensation which occurs through the intermediate formation of the alkoxycarbonyl derivative.