Xanthene[n]arenes: Exceptionally Large, Bowl-Shaped Macrocyclic Building Blocks Suitable for Self-Assembly

A new
class of macrocycles denoted as “xanthene­[n]­arenes” was synthesized. In contrast to most other
macrocycles, they feature a conformationally restricted bowl shape
due to the attached alkyl groups at the linking methylene units. This
facilitates the synthesis of cavitands and the self-assembly to molecular
capsules via noncovalent interactions. The derivatization potential
of the novel macrocycles was demonstrated on the xanthene[3]­arene
scaffold. Besides a deep cavitand and an oxygen-embedded zigzag hydrocarbon
belt[12]­arene, a modified macrocycle was synthesized that self-assembles
into a hydrogen-bonded tetrameric capsule, demonstrating the potential
of xanthene­[n]­arenes as a new set of macrocyclic
building blocks.

一种命名为“xanthene[n]arenes”的新型宏观环化合物被成功合成。与大多数其他宏观环化合物不同，它们因连接亚甲基单元上附着的烷基基团而呈现出构象受限的碗状形状。这一特性有利于空腔化合物的合成以及通过非共价相互作用实现分子胶囊的自我组装。在xanthene[3]arene支架上，新型宏观环的衍生化潜力得到了证实。除了合成了一种具有深层空腔和嵌氧的之字形碳氢化合物链的arene外，还合成了一种可自组装成氢键结合的四聚体胶囊的改性宏观环，从而展示了xanthene[n]arenes作为一系列新型宏观环构建块的可能性。