Synthesis and Asymmetric Recognition of Chiral Calixarenes

杯芳烃不仅可以作为金属离子的寄主分子，也可以作为带电和不带电有机分子的寄主分子。本研究的目的是设计这样的杯芳烃，可以不对称识别光学活性有机分子。研究策略是：(1)引入光学活性取代基和（ii）取代基在杯芳烃环上的不对称排列。在策略(1)的基础上合成的手性杯芳烃对手性客体分子具有选择性结合，易于通过圆二色性检测。策略(2)涉及一个新的想法，其中三个以上不同的取代基按(R)方向或(S)方向排列。然而，如果发生环反转，这些光学异构体可以外消旋。因此，我们开发了一种新的合成方法，可以抑制杯形[4]芳烃环的反转。最后利用手性填充高效液相色谱柱成功进行了光学分辨。这是产生环状的手性杯状[4]芳烃的光学分辨率的第一个例子。报道了几种使用这些手性杯芳烃进行不对称分子识别的尝试。

Calixarenes act as novel host molecules not only for metal ions but also for charged and uncharged organic molecules. The purpose of the present research was to design such calixarenes that can asymmetrically recognized optically-active organic molecules. The research strategies are (1) introduction of optically-active substituents and (ii) asymmetric arrangement of substituents on the calixarene ring. Chiral calixarenes synthesized on the basis of strategy (1) showed the selective binding toward chiral guest molecules, which was easily detected by circular dichroism.Strategy (2) involves a new idea in which more than three different substituents are arranged in (R) direction or (S) direction. however, if ring inversion takes place, these optical isomers can racemize. we thus developed a new synthetic method by which inversion of the calix[4]arene ring could he suppressed. We finally succeeded in optical resolution by using a chiral-packing HPLC column. This is the first example for optical resolution of ring-originating, chiral calix[4]arenes.Several attempts to use these chiral calixarenes for asymmetric molecular recognition were reported.