@article{oai:soar-ir.repo.nii.ac.jp:00019882,
 author = {Shoji, Taku and Maruyama, Mitsuhisa and Maruyama, Akifumi and Ito, Shunji and Okujima, Tetsuo and Toyota, Kozo},
 issue = {37},
 journal = {CHEMISTRY-A EUROPEAN JOURNAL},
 month = {Sep},
 note = {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., Article, CHEMISTRY-A EUROPEAN JOURNAL. 15(18):11903-11912 (2014)},
 pages = {11903--11912},
 title = {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},
 volume = {20},
 year = {2014}
}