Halohydrin

Halohydrins are a class of substances of organic compounds carrying a functional group at a carbon atom as a substituent and a halogen on a carbon atom adjacent to a hydroxy group.

They are usually prepared by halogenation of olefins in the presence of water. As the halogen source is here often N-bromosuccinimide (NBS ) or N- chlorosuccinimide (NCS). Another method is the reaction of epoxides with hydrogen halide acids.

In the presence of base, the halohydrin arises only as an intermediate stage, and there is an intramolecular cyclization to the epoxide instead. This is the reverse of the reaction for the preparation of halohydrins from epoxides with hydrogen halide acids.

Epoxidation reactions in biological systems can be catalyzed by Halohydrindehalogenasen.