Nucleophilic substitution at the halogen atom (halogenophilic reactions)

The key features of halogenophilic reactions defining their role in organic chemistry are considered. The results of studies of mechanisms involving a nucleophilic attack at the halogen atom (SN2Hal) are summarized. The main mechanistic evidence comes from the studies of halogen–metal exchange reactions. Primary attention is paid to the role of halogenophilic reaction as a competing process or a concealed mechanism in ordinary nucleophilic substitution reaction at carbon atoms. The bibliography includes 249 references.