Efficient Method for the Preparation of Aromatic Bromides and Iodides by Ferrocenium Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate-Catalyzed Halogenation with Bromine and Iodine Monochloride.

Direct iodination and bromination of various aromatic compounds with 1.1–2.0 molar amounts of iodine monochloride (ICl) and 1.1–3.0 molar amounts of bromine proceeded smoothly to afford the corresponding aromatic iodides and bromides, respectively, in good to excellent yields by using 0.05 molar amount of ferrocenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, Cp2FeB[3,5-(CF3)2C6H3]4 (1), in the presence of ZnO. Iodination of toluene in the coexistence of 0.5 molar amount of DDQ also proceeded to give iodotoluenes in high yield.