Nitrogen Dioxide-Catalyzed Electrophilic Iodination of Arenes.

Nitrogen dioxide is demonstrated to be an effective catalyst precursor for the iodination of alkoxy-substituted benzenes and naphthalenes. Different from the transition metal catalysts, nitrogen dioxide can be easily separated from the final products, and is free of heavy metal waste. Although the present catalyst precursor is toxic, it does not stain the final products due to its low-boiling character. No other reagents apart from 0.5 equiv. of iodine (I₂), 6.5 mol% nitrogen dioxide and acetonitrile solvent were used in the iodination, and basically all the iodine atoms in the iodine source were transferred to the iodination products, showing that the presented protocol is highly atom-economic and practical. [ABSTRACT FROM AUTHOR]