Approaches to new fluoride ion sources

Fluoride ion sources have been surveyed and perfluoroalkyl anions and hindered amine/HF adducts prepared and investigated as reagents. The perfluoroalkyl anions (I) and (II) have been used in an attempt to fluorinate various organic compounds such as alkyl halides, alkyl tosylates, aryl halides and acetyl chloride. The following new compounds have been synthesised and identified by glc-mass spec and, where possible, (^19)F nmr. These arose from reaction of the substrate with the perfluoroalkyl anion rather than with F(^-). Preliminary work on hindered amine bases, particularly proton sponge and tri-n-octylamine, with HF was undertaken, these being studied as possible soluble fluoride ion sources. Solid adducts were obtained in most cases from ether solutions and they were shown to behave as fluoride ion sources under various conditions.