High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols

Muhammet Uyanik, Hiroki Hayashi, Kazuaki Ishihara

Research output: Contribution to journalArticle

105 Citations (Scopus)

Abstract

The diverse biological activities of tocopherols and their analogs have inspired considerable interest in the development of routes for their efficient asymmetric synthesis. Here, we report that chiral ammonium hypoiodite salts catalyze highly chemo- and enantioselective oxidative cyclization of γ-(2-hydroxyphenyl)ketones to 2-acyl chromans bearing a quaternary stereocenter, which serve as productive synthetic intermediates for tocopherols. Raman spectroscopic analysis of a solution of tetrabutylammonium iodide and tert-butyl hydroperoxide revealed the in situ generation of the hypoiodite salt as an unstable catalytic active species and triiodide salt as a stable inert species. A high-performance catalytic oxidation system (turnover number of ~200) has been achieved through reversible equilibration between hypoiodite and triiodide in the presence of potassium carbonate base.We anticipate that these findings will open further prospects for the development of high-turnover redox organocatalysis.

Original languageEnglish
Pages (from-to)291-294
Number of pages4
JournalScience
Volume345
Issue number6194
DOIs
Publication statusPublished - Jan 1 2014
Externally publishedYes

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Tocopherols
Catalysis
Salts
Chromans
tert-Butylhydroperoxide
Cyclization
Ketones
Ammonium Compounds
Oxidation-Reduction
hypoiodous acid

All Science Journal Classification (ASJC) codes

  • Medicine(all)
  • General

Cite this

High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols. / Uyanik, Muhammet; Hayashi, Hiroki; Ishihara, Kazuaki.

In: Science, Vol. 345, No. 6194, 01.01.2014, p. 291-294.

Research output: Contribution to journalArticle

Uyanik, Muhammet ; Hayashi, Hiroki ; Ishihara, Kazuaki. / High-turnover hypoiodite catalysis for asymmetric synthesis of tocopherols. In: Science. 2014 ; Vol. 345, No. 6194. pp. 291-294.
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