Leaving groups in aliphatic nucleophilic

The fact that fluoride is a poor leaving group in aliphatic nucleophilic substitutions and the high volatility of fluoroaliphatic compounds are the keys to the Finkelstein synthesis of alkyl fluorides. An alkyl iodide, bromide, or tosylate is heated in a polar solvent vith an alkali fluoride and the volatile alkyl fluoride is removed by distillation during the reaction [30] (Scheme 2.11). For safe handling of primary alkyl fluorides it must be kept in mind that the even-membered compounds of this series are toxic, because they can be oxidatively metabolized to the poisonous fluoroacetate [31]. 

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