The direct esterification of carboxylic acids with perfluorinated alcohols mediated by XtalFluor-E is reported. The corresponding polyfluorinated esters are obtained in moderate to excellent yields with a broad range of carboxylic acids, including aromatic, heteroaromatic, aliphatic, and nonracemic chiral substrates, using only a slight excess (2 equiv) of the perfluorinated alcohol. Control experiments indicate that the reaction does not proceed through the formation of an acyl fluoride but most likely through a (diethylamino)difluoro-λ4-sulfanyl carboxylate intermediate.
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