A Fused [5]Helicene Dimer with a Figure‐Eight Topology: Synthesis, Chiral Resolution, and Electronic Properties

作者：Qifeng Zhou, Xudong Hou, Jinyi Wang, Yong Ni, Wei Fan, Zhengtao Li, Xiao Wei, Ke Li, Wei Yuan, Zhuofan Xu, Manzhou Zhu, Yanli Zhao, Zhe Sun, Jishan Wu · 发表于：Angewandte Chemie International Edition · 年份：2023 · DOI：10.1002/anie.202302266 · 被引用次数：63 · 研究领域：Synthesis and Properties of Aromatic Compounds、Advanced NMR Techniques and Applications、Fullerene Chemistry and Applications

Abstract Chiral shape‐persistent molecular nanocarbons are promising chiroptical materials; their synthesis, however, remains a big challenge. Herein, we report the facile synthesis and chiral resolution of a double‐stranded figure‐eight carbon nanobelt 1 in which two [5]helicene units are fused together. Two synthetic routes were developed, and, in particular, a strategy involving Suzuki coupling‐mediated macrocyclization followed by Bi(OTf) 3 ‐catalyzed cyclization of vinyl ether turned out to be the most efficient. The structure of 1 was confirmed by X‐ray crystallographic analysis. The isolated ( P , P )‐ and ( M , M )‐ enantiomers show persistent chiroptical properties with relatively large dissymmetric factors (| g abs |=5.4×10 −3 and | g lum |=1.0×10 −2 ), which can be explained by the effective electron delocalization along the fully conjugated belt and the unique D 2 symmetry. 1 exhibits local aromatic character with a dominant structure containing eight Clar's aromatic sextet rings.