Selective Production of Diiodobenzene and Iodobenzene from Benzene

Electrophilic Iodination of Organic Compounds Using Elemental Iodine or Iodides

“…Benzene and naphthalene were directly iodinated to iodobenzene (2) or 1-iodonaphthalene (4) using several iodinating systems (Table 1). Transformations using iodine and the oxidants chromium(VI) oxide, 18 sodium percarbonate (SPC) 19 or iodopentoxide 20 under anhydrous and strongly acidic conditions gave moderate to good yields of 2 (entries 1-3), while oxidative activation with polyvinylpyrrolidone-supported hydrogen peroxide (PVP-H 2 O 2 ) catalysed by tungstophosphoric acid, 21 the charcoal-supported complex Fe(NO 3 ) 3 •1.5N 2 O 4 , 22a xenon di- fluoride, 23 or with poly[styrene-(iodosodiacetate)] 27 could be performed under milder reaction conditions (entries 4, 5,8,11,16). Activation following iodide trapping by mercury(II) 24 or silver(I) 25 ions was also applied (entries 9, 10) and moderate to excellent yields obtained, while oxidative iodination by alkali metal iodides and potassium bromate under acidic conditions 22c (entries 7 and 13), concentrated sulfuric acid, 26 (entry 15), cerium(IV) trihydroxide hydroperoxide in aqueous sodium dodecyl sulfate (SDS), 22b (entries 6 and 12) or polymer-supported hydrogen peroxide 21 (entries 4 and 14) were also used for this derivatisation of benzene or naphthalene.…”

Regioselective iodination of arenes in ionic liquids mediated by SelectfluorTM reagent F-TEDA-BF4

“…3 The direct introduction of iodine into aromatic molecules is the most used methodology although the addition of activating agents is necessary, owing to the low electrophilicity of I 2 . Several methods using iodonium donating agents have therefore been developed, such as iodine-tetrabutylammonium peroxydisulfate, 4 BuLi-CF 3 CH 2 I, 5 iodinenitrogen dioxide, 6 iodine-F-TEDA-BF 4 , 7 iodine-iodine pentoxide, 8 iodine monochloride, 9 NIS-CF 3 SO 3 H, 10 iodine-mercury salts, 11 and NaOCl-NaI. 12 Most of these methods require toxic reagents or solvents and the reactions often occur with a low regioselectivity giving, besides the mono-iodo adducts, mixtures of poly-iodination products.…”

Advances in the direct iodination of aromatic compounds

“…The combinations of iodine and di-iodine pentoxide and of iodine and iodic acid have been used 28 to iodinate activated aromatic rings. The iodination of a series of o-hydroxyarylketones by the latter reagent, has been reported.…”