Direct α-Iodination of Aryl Alkyl Ketones by Elemental Iodine Activated by Chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane Bis(tetrafluoroborate)
Marjan Jereb, Stojan Stavber*, Marko Zupan
*Laboratory for Organic and Bioorganic Chemistry, ‘Jozef Stefan' Institute
and Department of Chemistry, University of Ljubljana, Jamova 39, 1000 Ljubljana,
Email: stojan.stavber
ijs.si
M. Jereb, S. Stavber, M. Zupan, Synthesis, 2003, 853-858.
DOI: 10.1055/s-2003-38689
Abstract
Selective introduction of an iodine atom at the α-carbonyl position in
various aryl alkyl ketones was effectively achieved by reaction of target
molecules with elemental iodine in the presence of N-F reagents such as
F-TEDA-BF4 (Selectfluor) as iodination mediators and methanol as the
solvent.
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Details
The document discusses the selective β-iodination of aryl alkyl ketones using elemental iodine activated by 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor F–TEDA–BF4). This method effectively introduces an iodine atom at the β-carbonyl position in various aryl alkyl ketones. The best results were achieved using methanol as the solvent. The study highlights the versatility of iodinated organic molecules in synthetic chemistry, particularly in carbon–carbon bond formation and their applications in medicine. Traditional methods for β-iodination of ketones are limited, often involving indirect approaches. The authors found that Selectfluor F–TEDA–BF4, a strong oxidizing agent, is an optimal mediator for direct iodination, providing high yields and regioselectivity. The method was tested on a range of substrates, including hydroxy and methoxy-substituted acetophenones, and heterocyclic ketones, consistently yielding β-iodo products. The study concludes that the I2/F–TEDA–BF4/MeOH system is a valuable tool for the efficient and selective iodination of aryl alkyl ketones, with potential applications in synthesizing iodinated compounds for various scientific and medicinal purposes.
Key Words
iodine, ketones, regioselectivity, fluorine, α-iodination, selectfluor
ID: J66-Y2003-1820
