Aromatic Bromination and Iodination with Mixtures of Antimony (V) Chloride and Halogens

Equimolar mixtures of SbCl5 and Br2 or I2 were found to be elegant reagents for the halogenation of certain aromatic substrates. In carbon tetrachloride, halogenobenzenes afforded the corresponding bromo- and iododerivatives with high para-selectivities (more than 95%) in good yields. The bromination of aromatic compounds with deactivating groups, such as ethyl benzoate and nitrobenzene, was simply achieved in 1,2-dichloroethane. Based on competitive halogenation data, the attack of BrCl or ICl (both formed in situ) on aromatics has been suggested.