N-Fluoropyridinium salts provide a new system of fluorinatingagents by which a wide range of nucleophilic substrates differing in reactivity can be fluorinated due to the varying degree of fluorinating power and also fluorinated very selectively through structural alteration. The scope of selective fluorination should be broadened considerably on the basis of the present results. The N-fluoropyridinium
Catalysis of the reaction between fluorine and a range of 2-substituted carbonyl compounds has been investigated. Most notably, the preparation of diethyl-2-fluoromalonate has been achieved in high yield by fluorination of diethylmalonate in the presence of hydrated copper nitrate. Reactions between fluorine and carbanions derived from 2-substituted carbonyl compounds, including phosphonates, sulphones