One-pot aromatic bromination-rearrangement catalyzed by GaCl₃

Reaction of monoalkylbenzenes with bromine in the presence of a catalytic amount of GaCl₃ (5 mol %) initially gives o/p-bromination products, which are converted into mixtures containing considerable amounts of the m-brominated products. Notably, the bromination of dimethyl-, trimethyl-, and tetramethylbenzenes gives dibromo- and/or tribromoarenes, which are converted into monobromoarenes.