halohydriinimenetelmä

The halohydrin method is a chemical reaction used to synthesize halohydrins from alkenes. A halohydrin is a molecule that contains both a halogen atom and a hydroxyl group attached to adjacent carbon atoms. This reaction is typically carried out by treating an alkene with a halogen, such as bromine or chlorine, in the presence of water. The water acts as a nucleophile, attacking the intermediate bromonium or chloronium ion formed after the halogen adds to the double bond. The regioselectivity of the reaction, meaning which carbon atom the hydroxyl group attaches to, is influenced by steric and electronic factors. The more substituted carbon atom of the original double bond will typically receive the hydroxyl group due to the greater stability of the partial positive charge developing on it during the reaction. This method is a valuable tool in organic synthesis for introducing oxygen and halogen functionalities into organic molecules, often serving as a precursor to epoxides through subsequent base-induced cyclization. For instance, the reaction of an alkene with NBS (N-bromosuccinimide) in aqueous DMSO is a common way to perform this transformation. The resulting halohydrins can be further manipulated to create a variety of other functional groups.