Electrophilc ipso-substltiitlon and some unique reaction behavior of 1,3,6-tri-tri-butylazulene

Taku Shoji, Shunji Ito, Tetsuo Okujima, Junya Higashi, Ryuji Yokoyama, Kozo Toyota, Masafumi Yasunami, Noboru Morita

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.

Original languageEnglish
Pages (from-to)1554-1563
Number of pages10
JournalEuropean Journal of Organic Chemistry
Issue number10
Publication statusPublished - 2009 Apr

Keywords

  • Aromatic substitution
  • Azulenes
  • Cycloaddition
  • Electrochemistry
  • Ipso-Substitution

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

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