Hydrogen peroxide-or sodium hypochlorite-induced bromination of 1-arylbut-2-enes

Bromination of 1-arylbut-2-enes in the system HBr or NaBr (KBr)-HX]-H₂O₂ (or NaOCl) under relatively mild conditions leads to electrophilic addition of bromine or hypobromous acid at the side-chain double bond. Under more severe conditions, the process is accompanied by bromination of the aromatic ring. Treatment of the title compounds with peroxy acids (RCOOH-H₂O₂) gives the corresponding epoxy derivatives which react with HBr and oxygen-containing nucleophiles to produce α-bromo alcohols, diols, and diol acetates.