The reaction of alcoholates with esters of perfluoroalkylethanoic acid (I) and 3-perfluoroalkyl-3-fluoro-propenoic acid (II) has been studied. Formation of ethers of the enol ester III or the acetal IV depends on the stoichiometric conditions used. The formation of the products proceeds via a Michael-type addition and elimination of fluoride ions from the enolate formed as an intermediate.