Synthesis and Isolation of Antiaromatic Expanded Azacoronene via Intramolecular Vilsmeier-Type Reaction
Synthesis and Isolation of Antiaromatic Expanded Azacoronene via Intramolecular Vilsmeier-Type Reaction
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通过分子内 Vilsmeier 型反应合成和分离抗芳香族膨胀氮杂苯
DOI：
10.1021/jacs.9b09260
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发表时间：
2019
影响因子：
15
通讯作者：
Uno Hidemitsu
中科院分区：
文献类型：
--
作者：
Oki Kosuke;Takase Masayoshi;Mori Shigeki;Uno Hidemitsu
通过部分未稠合的 HPHAC2 的 Vilsmeier 型反应合成了扩展的六吡咯并六氮杂苯 (HPHAC)1+ 的反芳香族阳离子。 X射线衍射分析揭示了吡咯部分之间具有次甲基键合的七元环的形成。尽管 1+ 是单阳离子，但在 1 H NMR 谱中可以清楚地观察到外围乙基质子的高场位移，表明 24π 反芳香性。全局反芳香性也得到了与核无关的化学位移和感应电流密度计算的各向异性的支持。在循环伏安法测量中，Cation1+ 显示出两次可逆氧化和一次不可逆还原。用 NOSbF6 处理 1+ 得到具有 22π-电子共轭的芳香族三阳离子 13+。
An antiaromatic cation of the expanded hexapyrrolohexaazacoronene (HPHAC)1+was synthesized by a Vilsmeier-type reaction of the partially unfused HPHAC2. X-ray diffraction analysis revealed the formation of a seven-membered ring with a methyne linkage between the pyrrole moieties. Although1+is a monocation, upfield shifts of the peripheral ethyl protons were clearly observed in the1H NMR spectra, indicating 24π antiaromaticity. Global antiaromaticity was also supported by nucleus-independent chemical shift and anisotropy of the induced current density calculations. Cation1+displayed two reversible oxidations and one irreversible reduction in the cyclic voltammetry measurements. Treatment of1+with NOSbF6gave aromatic trication13+with 22π-electron conjugation.