H-bonding
activation in the regioselective acetylation of vicinal
and 1,3-diols is presented. Herein, the acetylation of the hydroxyl
group with acetic anhydride can be activated by the formation of H-bonds
between the hydroxyl group and anions. The reaction exhibits high
regioselectivity when a catalytic amount of tetrabutylammonium acetate
is employed. Mechanistic studies indicated that acetate anion forms
dual H-bonding complexes with the diol, which facilitates the subsequent
regioselective monoacetylation