Catalyzed Reformatsky Reactions with Ethyl Bromofluoroacetate for the Synthesis of α-Fluoro-β-hydroxy Acids

The presence of catalytic amounts of CeCl3 improves yields and simplifies procedure in the Reformatsky reactions of ethyl bromofluoroacetate with aldehydes and ketones to generate diastereomeric mixtures of α-fluoro-β-hydroxy esters, some of which can be separated by crystallization or column flash chromatography. Diastereomerically pure α-fluoro-β-hydroxy acids are obtained by mild alkaline hydrolysis of the resolved α-fluoro-β-hydroxy esters. Detailed NMR data of new α-fluoro-β-hydroxy esters and α-fluoro-β-hydroxy acids are also presented.