A From saturated compounds

The fact that exchange occurs to produce, in each case, the fluorocarbon derivative is quite consistent with the general observation that exchange generally proceeds to give a product where the metal is bonded preferentially to the most electronegative group [33]. 

The perfluoro- - and -/-propyl and - -heptyl derivatives [22, 34—36] are the most stable of the simple alkyl series. 

This difference is obviously due to the difficulty in producing a double bond at a bridgehead position. Nevertheless, elimination of lithium fluoride does occur, especially at reflux temperatures the bridgehead alkene 10.8A, which probably has only a transitory existence or may even be more appropriately described as a diradical, may be trapped with furan. 

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