Final answer:
In hydrohalogenation reactions, the presence of peroxides like ROOR leads to radical-mediated anti-Markovnikov addition of hydrogen halides to alkenes, where the halogen attaches to the less substituted carbon atom. Peroxides can facilitate the homolytic cleavage that generates radicals, leading to the initiation of a radical chain reaction mechanism.
Step-by-step explanation:
When peroxides are present in hydrohalogenation reactions, they facilitate a radical mechanism as opposed to the typical carbocation mechanism seen in these reactions. Peroxides, like ROOR, can produce radicals which then lead to the anti-Markovnikov addition of hydrogen halides to alkenes.
The peroxide effect is relevant in the context of hydrohalogenation, where hydrogen peroxide (H₂O₂) or other peroxides can result in radical formation. This is due to the fact that peroxides are prone to homolytic cleavage, leading to the formation of free radicals which can then react with alkenes in a radical addition reaction.