Nucleophilic Substitution Reactions

Alkyl halides undergo many reactions in which a nucleophile displaces the halogen atom bonded to the central carbon of the molecule. The displaced halogen atom becomes a halide ion.

Some typical nucleophiles are the hydroxy group ( OH), the alkoxy group (RO ), and the cyanide ion ( C N). Reaction of these nucleophiles with an alkyl halide (R&bond;X) gives the following reactions and products:

The halogen ion that is displaced from the carbon atom is called the leaving group, and the overall reaction is called a nucleophilic substitution reaction.