Fluoride ion transfer and stabilisation of reactive ions

Some general guidelines for the generation of salts with high fluoride ion donor ability are discussed. A preliminary scale for a limited number of fluoride ion donors is presented, cations are classified according to their anion–cation interaction properties. Examples for fluoride ion transfer reactions are given and the influence of anion–cation interaction on the stabilisation of reactive anions is discussed. In our work mainly TAS fluoride (Me2N)3S+Me3SiF2− has been used as fluoride ion source: (a) for fluoride ion transfer to coordinatively unsaturated sulfur species, to SN and SO multiple bond systems, to SN, PN and CN heterocycles, (b) for the stabilisation of primary products of nucleophilic attacks and of intermediates in isomerisation processes or of intermediates in polymerisation processes, (c) for the generation of “naked” anions by silicon-element bond cleavage, and (d) for the activation of element-fluorine bonds by anion formation.