Superelectrophilic bromination of deactivated aromatic rings with tribromoisocyanuric acid-an experimental and DFT study

The reaction of deactivated arenes with tribromoisocyanuric acid (TBCA) in 98% H2SO4 produced bromoarenes in good yields. The acidity of the medium controls the strength of the brominating agent and the amount of polybrominated products. DFT calculations at B3LYP/6-311++G∗∗ level showed that the protonated TBCA (a superelectrophilic species) can easily transfer Br+ to deactivated arenes, in order to decrease internal charge-charge repulsion.