A New α -Iodination of Ketones Using Iodine-Ammonium Cerium(IV) Nitrate in Alcohol or Acetic Acid

Abstract

The direct α-iodination of various ketones using iodine-ammonium cerium(IV) nitrate in acetic acid or alcohol gave the corresponding α-iodo ketones in high yields. The effect of cerium salt on the iodination of ketones, and the iodination of 5α-cholestan-3-one using several methods are also discussed. In the reaction of 3,3,5-trimethylcyclohexanone and unsymmetrical ketones, such as 2-hexanone and 2-heptanone, using methanol, ethanol, 1-propanol, and 2-propanol, the regioselective iodination product was obtained. In the case of bromination, the reaction of ketones with bromine and ammonium cerium(IV) nitrate also yielded the corresponding α-bromo ketones.

Eco‐Mn Ecocatalysts: Toolbox for Sustainable and Green Lewis Acid Catalysis and Oxidation Reactions

“…Indeed, they have a high reactivity and can be used as intermediates for the synthesis of useful high added‐value compounds, including pharmacologically active heterocycles . The synthesis of α ‐iodoketones frequently involves the formation of electrophilic derivatives of iodine, using I 2 in combination with various oxidizing reagents, such as SeO 2 , Ce(IV) ammonium nitrate or m ‐iodosobenzoic acid . Despite their efficiency, these methods use toxic or unstable oxidizing reagents that are incompatible with the requirements of the REACH regulation.…”

Electrophilic Iodination of Organic Compounds Using Elemental Iodine or Iodides

“…48,52,[130][131][132][133][134][135] Unsymmetrical ketones were preferentially iodinated at the most occupied a-carbon atom, but in the case of iodination with the molecular iodine and ammonium cerium(IV) nitrate tandem in alcohol, the regioselectivity of functionalisation could be regulated by the structure of the alcohol and reaction temperature (Table 14). 140 At lower temperature, the C3-position in alkan-2-ones 184 was preferentially iodinated in methanol and isopropyl alcohol (entries 1, 3, 5, and 7), in methanol the functionalisation being more regiospecific and efficient. At higher reaction temperature in methanol, the same regioselectivity was observed (entries 2 and 6), while in isopropyl alcohol the C1-position was preferentially iodinated (entries 4 and 8).…”

Molecular Iodine-Mediated α-Iodination of Carbonyl Compounds

“…However, I 2 in DME was found not to be selective for unsymmetrical alkyl ketones 14 and to afford mixtures of α-iodoketones 15-17 with the 3-iodo isomer 15 as the major product (Scheme 7). 17 The problem of selectivity to form either the 3-iodo isomers 15 or α,αp-diiodo derivatives 17 can be circumvented by the use of an iodine-CAN mixture in alcohols [21][22][23] or acetonitrile, 22 respectively. Several derivatives of indan-1-one and 3,4-dihydronaphthalen-1(2H)-one (2 equiv.)…”