Activation of I2 with aryl iodine(III) for the iodination of deactivated arenes

A highly effective method for iodinating deactivated aryl rings is reported, using organic solvents (CH2Cl2, CHCl3) where traditional methods typically require concentrated H2SO4. A new aryl iodine(III) system oxidizes I2 in the presence of trifluoroacetic anhydride as a water scavenger and catalytic H2SO4 in cases of very deactivated rings. The aryl iodine(III) oxidants, 4-nitrophenyliodine bis(trifluoroacetate) (NPIFA), 3-iodosylbenzoic acid (3-IBA), or 2,4-dichloro-5-iodosylbenzoic acid (3-IBACl2) are applied based on separability and reactivity of target substrates, and their reduced forms are recovered by simple acid/base extractions, demonstrating excellent reusability. Leveraging this, iodinated products are isolated without the need for chromatography. The method is suitable for use under benchtop conditions, and exhibits high atom efficiency, fully incorporating I2 into products.