Aerobic Oxidative Iodination of Organic Compounds with Iodide Catalyzed by Sodium Nitrite

Selective and efficient iodinations of organic compounds were achieved by an aerobic oxidative process catalyzed by sodium nitrite using potassium iodide in acidic media. Using the potasasium iodide (KI)/air/sodium nitrite (NaNO2; cat.)/sulfuric acid (H2SO4) iodinating system, activated and moderately deactivated aromatic compounds were exclusively or preferentially iodinated at the para position. In protic solvents ketones and 1,3-dicarbonyl compounds were iodofunctionalized at the a carbonyl position, while in the case of aryl methyl ketones bearing an activated aromatic ring, the regioselectivity of iodination could be directed by the solvent used. In acetonitrile (MeCN) the aromatic ring was selectively iodinated, while in aqueous rethanol (EtOH) functionalization of the methyl carbon atom took place. Alkenes were transformed to vicinal iodohydrins or vicinal iodoalkoxy derivatives following Markovnikov-type regioselectivity and anti stereoselectivity, while 1,2-diiodoalkenes with preferentially E orientation were formed from alkynes.