Synthesis and Conformational Properties of Nonsymmetric Pillar[5]arenes and Their Acetonitrile Inclusion Compounds
作者:Yuhui Kou、Hongqi Tao、Derong Cao、Zhiyong Fu、Dieter Schollmeyer、Herbert Meier
DOI:10.1002/ejoc.201000718
日期:2010.11
The catalytic cyclocondensation of 1-butoxy-4-methoxy-2,5-bis(methoxymethyl)benzene (1d) affords a statistical mixture of the regioisomeric pillar[5]arenes 3a–d in high yield. The alkoxy groups are arranged stereoselectively in a mode so that they avoid steric interactions. The rotation of the benzene rings is, at room temperature, fast in terms of the NMR timescale and leads to a de facto Cs symmetry
1-丁氧基-4-甲氧基-2,5-双(甲氧基甲基)苯(1d)的催化环缩合反应以高产率提供了区域异构柱[5]芳烃3a-d的统计混合物。烷氧基以某种方式立体选择性地排列,以避免空间相互作用。在室温下,苯环的旋转在 NMR 时间尺度方面很快,并导致 3a-c 的事实上的 Cs 对称和 3d 的 C5h 对称。所有四种结构异构体都可以封装两个 CH3CN 客体分子。结构测定基于四种晶体结构分析(构成)和 NMR 光谱测量(构象)。