Reactions of potassium fluoride in glacial acetic acid with chlorocarboxylic acids, amides, and chlorides. The effect of very strong hydrogen bonding on the nucleophilicity of the fluoride anion

Abstract

Although KF is very soluble in glacial acetic acid, the nucleophilicity of the fluoride ion therein is much reduced by the very strong hydrogen bonding which occurs between it and the solvent. The fluoride is in effect enhancing the nucleophilicity of the hydroxyl oxygen atom of the carboxylic acid group. Reaction of chlorocarboxylic acids and their derivatives with this reagent produces acetoxy- instead of the anticipated fluoro-derivatives. The acid chlorides Cl(CH₂)_nCOCl, acids Cl(CH₂)_nCO₂H, and some amides Cl(CH₂)_nCONH₂(n= 1,2,3, etc.) have been investigated and their reactions with KF in acetic acid elucidated. In addition to substitution, lactonization and elimination reactions may also occur. Some new products have been isolated and characterized. Related reactions involving KF alone are reported; in some of these polymerization takes place.