Chemical Transformations of Push-Pull Fluorenones: Push-Pull Dibenzodicyanofulvenes as well as Fluorenone- and Dibenzodicyanofulvene-Tetracyanobutadiene Conjugates
Chemical Transformations of Push-Pull Fluorenones: Push-Pull Dibenzodicyanofulvenes as well as Fluorenone- and Dibenzodicyanofulvene-Tetracyanobutadiene Conjugates
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推拉芴酮的化学转化：推拉二苯并二氰基富烯以及芴酮和二苯并二氰基富烯-四氰基丁二烯缀合物
DOI：
10.1039/c9ob02706h
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发表时间：
2020
影响因子：
3.2
通讯作者：
Yosuke Nakamura
中科院分区：
文献类型：
--
作者：
Shin-ichiro Kato;Tomokazu Kijima;Yoshihito Shiota;Tsukasa Abe;Satoshi Kuwako;Hidenori Miyauchi;Naoki Yoshikawa;Kazunari Yoshizawa;Toshitada Yoshihara;Seiji Tobita;Yosuke Nakamura
以苯并环戊二烯醌（BPO）衍生物为原料，通过区域选择性[4 + 2]环加成（CA）和[4 + 1]逆环加成（RCA）反应，合成了一类具有推拉结构的芴酮（FO）.在TiCl 4和吡啶存在下，用丙二腈处理所得的FOs，可以很容易地将其转化为二苯并二氰基富烯（DBDCF）。FOs和DBDCF表现出分子内电荷转移（ICT），表现为在350-650 nm处的吸收和两性电化学行为。此外，含有CC键的FO和DBDCF与四氰基乙烯在形式[2 + 2] CA中反应，然后进行逆向电环化，得到空间拥挤的四氰基丁二烯（TCBD）缀合物。因此，与丁二烯部分相邻的芳环上的取代基（H或Me）决定丁二烯是采用S-顺式还是S-反式构象，从而控制所得TCBD的物理化学性质。TCBD结合物显示ICT吸收（≤800 nm）以及多达四个可逆还原步骤。
Push–pull fluorenones (FOs) were synthesized by treating a benzopentalenequinone (BPO) derivative with alkynes that bear an electron-rich aniline moiety via a regioselective [4 + 2] cycloaddition (CA) followed by a [4 + 1] retrocycloaddition (RCA). The resulting FOs were readily converted into dibenzodicyanofulvenes (DBDCFs) by treatment with malononitrile in the presence of TiCl4 and pyridine. The FOs and DBDCFs exhibit intramolecular charge-transfer (ICT) that manifests in absorptions at 350–650 nm and amphoteric electrochemical behavior. Furthermore, FOs and DBDCFs that contain a CC bond react with tetracyanoethylene in a formal [2 + 2] CA followed by a retro-electrocyclization to afford sterically congested tetracyanobutadiene (TCBD) conjugates. The substituent (H or Me) on the aromatic ring adjacent to the butadiene moiety thereby determines whether the butadiene adopts an s-cis or s-trans conformation, and thus controls the physicochemical properties of the resulting TCBDs. The TCBD conjugates exhibit ICT absorptions (≤800 nm) together with up to four reversible reduction steps.