关键词: 单溴代反应, 有机高价碘试剂, 催化氧化反应, 芳香化合物

Abstract:

Brominated aromatic compounds have considerable importance in the bulk and fine chemical industries, and they are also found widespread used as intermediates in organic chemistry, for example, in cross-coupling reactions. The preparation of brominated aromatic compounds with molecular bromine is a well-known reaction in organic chemistry. The method requires transition metal-based catalysts and the side product gene-rated in the course is corrosive and toxic hydrogen bromide. To improve the bromination process, considerable efforts especially in recently have been devoted and several bromination reagents have been successfully used in place of molecular bromine, and now the research in exploring the scope of it is still a much-sought process. We have developed an efficient monobromination of electron-rich aromatic compounds catalyzed by iodine or ammonium iodide. In our method, a catalytic amount of molecular iodine or ammonium iodide reacted with benzene and m-chloroperbenzoic acid in the presence of p-toluenesulfonic acid to form the recyclable hypervalent iodine intermediate, with which the bromination of electron-rich aromatic compounds and potassium bromide was fast in THF at room temperature, providing regioselective monobrominated products in good yields. The method has some advantages such as mild reaction conditions, simple procedure and good yields.

Key words: Monobromination, Hypervalent iodine reagent, Catalytic oxidation, Aromatic compound