Replacement of a carboxyl function by fluorine, fluorodecarboxylation, is a new process that can be accomplished by the reaction of alkanoic acids with xenon difluoride. Primary, tertiary, and benzylic acids perform best in the reaction, which is conducted at room temperature in methylene chloride or chloroform solution. A reaction mechanism is proposed in which the acid is initially converted to a fluoroxenon ester, RCO2XeF. The esters of the primary and secondary acids react by nucleophilic displacement by fluoride, as evidenced by incorporation of 18F− and no reactions common to free radicals or carbocations. The esters of the tertiary and benzylic acids react by converting to free radicals that can be further oxidized to carbocations. Thus incorporation of 18F− and racemization are observed with α-methoxy-α-trifluoromethylphenylacetic acid. Hydroxyl and amino functions inhibit the reaction. Aromatic and vinylic acids do not react.

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Aryltriazenes react with aromatic solvents in the presence of trifluoroacetic acid to produce biaryls. The mechanism of the reaction involves the formation of arenediazonium trifluoroacetates which lose nitrogen to give mainly aryl radicals.