Syntheses and Properties of Strained Polycyclic Compounds

近年来，人们对具有特殊结构、电子和光学性质的新型富碳材料的设计和构造给予了极大的关注。然而，尽管具有吸引人的结构特征，具有圆柱形结构的π共轭富碳大环仍然是一个合成挑战，尽管已经报道了几种制备相关带状分子的尝试。在这项研究中，我们研究了第一个[4_6]对环十二烷衍生物的合成和表征，其中六个对苯基和丁二炔单元交替连接，形成高度不饱和的圆柱形π共轭体系。本方法的一个关键特征是利用杜瓦苯作为角状对亚苯基合成子。因此，从相应的六(杜瓦苯)化合物以光化学方法生成了[4_6]对环十二烷衍生物，它是一种高度应变但可分离的化合物。目前的结果清楚地表明，我们的杜瓦苯构建块方法具有很高的合成潜力，可以构建难以从平面苯衍生物制备的应变苯大环。

Recently much attention has been focused on the design and construction of novel carbon-rich materials with unusual structural, electronic and optical properties. Despite the fascinating structural features, however, π-conjugated carbon-rich macrocycles with a cylindrical structre still remain as a synthetic challenge, although several attempts to prepare related belt-shaped molecules have been reported. In this study we examined the synthesis and characterization of the first [4_6]paracyclophanedodecayne derivative, in which six p-phenylene and butadiyne units are connected alternatively to form a highly unsaturated cylindrical π-conjugated system. A key feature in the present approach is exploitation of a Dewar benzene as an angular p-phenylene synthon. Thus, [4_6]paracyclophanedodecayne derivative has been photochemically generated from the corresponding hexakis(Dewar benzene) compound as a highly strained but isolable compound. The present results clearly demonstrate the high synthetic potential of our Dewar benzene building block approach for the construction of strained phenylene macrocycles that are difficult to prepare from planar benzene derivatives.