Dynamic Figure Eight Chirality: Multifarious Inversions of a Helical Preference Induced by Complexation

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• 作者：Ryo Katoono ; Yuki Tanaka ; Keiichi Kusaka ; Kenshu Fujiwara ; Takanori Suzuki
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：August 7, 2015
• 年：2015
• 卷：80
• 期：15
• 页码：7613-7625
• 全文大小：802K
• ISSN：1520-6904

文摘

We demonstrate two types of inversion of a helical preference upon the 1:1 complexation of a dynamic figure eight molecule with a guest molecule through the controlled transmission of point chirality. We designed a series of macrocycles that prefer a nonplanar conformation with figure eight chirality. These macrocycles are composed of a chirality-transferring unit (terephthalamide) and a structure-modifying unit (two o-phenylene rings spaced with a varying number of triple bonds). The former unit provides a binding site for capturing a guest molecule through the formation of hydrogen bonds. The attachment of chiral auxiliaries to the former unit induces a helical preference for a particular sense through the intramolecular transmission of point chirality. For relatively small-sized macrocycles, the preferred sense was reversed upon complexation with an achiral guest. Contrary preferences before and after complexation were both seen for chiral auxiliaries associated with a figure eight host through two-way intramolecular transmission of the single chiral source. Alternatively, the helical preference induced in relatively large-sized macrocycles was reversed only when a figure eight host formed a 1:1 complex with a particular enantiomeric guest through the supramolecular transmission of point chirality in the guest. This stereospecific inversion of a helical preference is rare.