A process for highly regioselective esterification and ester cleavage on unsaturated sugar compounds with the aid of lipases and esterases, and products which can be prepared by this process. Highly regioselective esterifications and ester cleavages can be carried out on unsaturated sugar compounds with the aid of lipases and esterases. Lipases from microorganisms or from the pancreas and liver of animals are preferably used.