Nucleofuge

A nucleofuge is a leaving group which retains the lone pair from its previous bond with another species. For example, in the SN2 mechanism a nucleophile attacks an organic compound containing the nucleofuge (the bromo group) which simultaneously breaks the bond with the nucleofuge.



After a reaction nucleofuges may contain either a negative or a neutral charge; this is governed by the nature of the specific reaction.

The word 'nucleofuge' is commonly found in older literature, but its use has been discontinued in current literature.