Synthesis of Redox-Active, Intramolecular Charge-Transfer Chromophores by the [2+2] Cycloaddition of Ethynylated 2H-Cyclohepta[b]furan-2-ones with Tetracyanoethylene
作者:Taku Shoji、Junya Higashi、Shunji Ito、Tetsuo Okujima、Masafumi Yasunami、Noboru Morita
DOI:10.1002/chem.201003628
日期:2011.4.26
Ethynylated 2H‐cyclohepta[b]furan‐2‐ones 5–15 have been prepared by Pd‐catalyzed alkynylation of 3‐iodo‐5‐isopropyl‐2H‐cyclohepta[b]furan‐2‐one (2) with the corresponding ethynylarenes or the reaction of 2‐iodothiophene with 3‐ethynyl‐5‐isopropyl‐2H‐cyclohepta[b]furan‐2‐one (4) under Sonogashira–Hagihara conditions. Compounds 5–15 reacted with tetracyanoethylene in a formal [2+2] cycloaddition reaction,
乙炔化2 ħ -环庚[ b ]呋喃-2-酮5 - 15已经制备由3-碘-5-异丙基2的Pd-催化的炔基ħ -环庚[ b ]呋喃-2-酮(2用)在Sonogashira-Hagihara条件下,相应的乙炔基芳烃或2-碘噻吩与3-乙炔基-5-异丙基-2 H-环庚七[ b ]呋喃-2-酮(4)的反应。化合物5 – 15在正式的[2 + 2]环加成反应中与四氰基乙烯反应,然后将最初形成的[2 + 2]环加合物环丁烯开环,得到相应的1,1,4,4-四氰基丁二烯(TCBD)生色团16 – 26的高产。通过UV / Vis光谱和理论计算研究了2 H-环庚[ b ]呋喃-2-酮环与TCBD受体部分之间的分子内电荷转移相互作用。新颖TCBD衍生物的氧化还原行为16 - 26用循环伏安法和差示脉冲伏安法检查了它们的化学性质,这揭示了多步电化学还原性质,这取决于分子中TCBD单元的数目。此外,在电化学还原条件下,通过UV