Triptycene-Based Ladder Polymers with One-Handed Helical Geometry
Triptycene-Based Ladder Polymers with One-Handed Helical Geometry
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DOI：
10.1021/jacs.8b13865
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发表时间：
2019-03-20
影响因子：
15
通讯作者：
Swager, Timothy M.
中科院分区：
文献类型：
--
作者：
Ikai, Tomoyuki;Yoshida, Takumu;Swager, Timothy M.
本文报道了一种通过含有双[2-(4-烷氧基苯基)乙炔]基团的手性三茂铁烯在分子内环化来合成光学活性梯形分子和聚合物的方法。亲电引发的环化反应在空间因子的作用下远离三丁三烯的桥头碳原子，从而产生单手扭曲的梯形单元，没有任何可检测到的副产物。此外，这种分子内环化的定量和区域选择性的性质使我们能够合成具有光学活性的梯形聚合物，其具有明确的单手螺旋构型，其中同质共轭二苯并[a，h]菲单元沿主链螺旋排列。这种合成路线使各种纳米级螺旋梯形结构的构建成为可能，并提供了进入新手性材料的途径。
Here we report an efficient synthesis of optically active ladder-type molecules and polymers through intramolecular cyclization of chiral triptycenes containing bis[2-(4-alkoxyphenyl)ethynyl]phenylene units. The electrophile-induced cyclization reactions are directed away from the bridgehead carbon atoms of triptycene by steric factors, thereby producing one-handed twisted ladder units without any detectable byproducts. Moreover, the quantitative and regioselective nature of this intramolecular cyclization allowed us to synthesize optically active ladder polymers with a well-defined one-handed helical geometry in which homoconjugated dibenzo[a,h]anthracene units are helically arranged along the main chain. This synthesis route enables the construction of a variety of nanoscale helical ladder architectures and provides an entry into new chiroptical materials.