Synthesis of 1,3-Bis(tetracyano-2-azulenyl-3-butadienyl)azulenes by the [2+2] Cycloaddition-Retroelectrocyclization of 1,3-Bis(azulenylethynyl)azulenes with Tetracyanoethylene

Taku Shoji, Mitsuhisa Maruyama, Akifumi Maruyama, Shunji Ito, Tetsuo Okujima, Kozo Toyota

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

1,3-Bis(azulenylethynyl)azulene derivatives 9-14 have been prepared by palladium-catalyzed alkynylation of 1-ethynylazulene 8 with 1,3-diiodoazulene 1 or 1,3-diethynylazulene 2 with the corresponding haloazulenes 3-7 under Sonogashira-Hagihara conditions. Bis(alkynes) 9-14 reacted with tetracyanoethylene (TCNE) in a formal [2+2] cycloaddition- retroelectrocyclization reaction to afford the corresponding new bis(tetracyanobutadiene)s (bis(TCBDs)) 15-20 in excellent yields. The redox behavior of bis(TCBD)s 15-20 was examined by using CV and differential pulse voltammetry (DPV), which revealed their reversible multistage reduction properties under the electrochemical conditions. Moreover, a significant color change of alkynes 9-14 and TCBDs 15-20 was observed by visible spectroscopy under the electrochemical reduction conditions.

Original languageEnglish
Pages (from-to)11903-11912
Number of pages10
JournalChemistry - A European Journal
Volume20
Issue number37
DOIs
Publication statusPublished - 2014 Sep 8

Keywords

  • azulene
  • cycloadditions
  • donor-acceptor system
  • electrochemistry
  • redox chemistry

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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