Superactivity and dual reactivity of the system N-iodosuccinimide-H2SO4 in the iodination of deactivated arenes

Abstract
Dissolution of N-iodosuccinimide in sulfuric acid gives rise to electrophilic iodine-containing species which are capable of successfully iodinating aromatic compounds with electron-withdrawing substituents in the temperature range from 0 to 20°C. The iodination in sulfuric acid is effected by both protonated N-iodosuccinimide and IOS(O)(OH+)OH intermediate.