Carbon Flatland: Planar Tetracoordinate Carbon and Fenestranes
Carbon Flatland: Planar Tetracoordinate Carbon and Fenestranes
复制标题
DOI：
10.1002/chin.200718243
复制
发表时间：
2007-05
期刊：
影响因子：
--
通讯作者：
R. Keese*
中科院分区：
文献类型：
--
作者：
R. Keese*
1874 年已知的光学活性化合物的共同结构特征使 van’t Hoff 和 Le Bel 独立得出结论：Cabcd 类型的四配位碳化合物必须具有四面体排列，而不是平面排列。 1, 2 由于范特霍夫将这些结构特征与价键的方向而不是扭曲的四面体联系起来，他的合理化立即吸引了做实验的化学家。结构有机化学中的这一“量子步骤”，与原子键和符号的图形表示相结合，是有机化合物及其结构领域爆炸性扩展的起点。可能的外消旋作用的开放侧翼——动力学稳定性的程度保持了数十年。这个问题在范特霍夫 1896 年至 1911 年间工作的柏林并没有受到关注。根据 E. Fischer 在柏林期间的研究助理 B. Helferich（后来成为莱比锡和波恩的教授）的说法，这个问题没有被讨论过。 3 当光学活性化合物因不对称碳原子键断裂而发生外消旋化机制时，未发现任何豁免情况，最终认为光学活性有机化合物的自外消旋化不太可能发生。 4 对构型反演的新兴趣是由 Hoffmann、Alder 和 Wilcox 于 1970 年讨论平面四配位碳的 MO 时引发的。 5
The common structural features of optically active compounds, known in 1874, led van’t Hoff and, independently, Le Bel to the conclusion that tetracoordinate carbon compounds of type Cabcd must have a tetrahedral rather than a planar arrangement. 1, 2 Since van’t Hoff related these structural features to the orientation of valence bonds rather than to a distorted tetrahedron, his rationalization appealed immediately to chemists doing experiments. This ‘quantum step’in structural organic chemistry, in combination with the graphical representation of bonds and symbols for atoms, was the starting point for the explosive expansion in the realm of organic compounds and their structures. The open flank of a possible racemizationsthe extent of the kinetic stabilitysremained for many decades. This problem was of no concern in Berlin, where van’t Hoff worked during 1896-1911. According to B. Helferich, research assistant to E. Fischer during these years in Berlin (later Professor at Leipzig and Bonn), this question was not discussed. 3 An autoracemization of optically active organic compounds was eventually considered unlikely when no exemption was found from a racemization mechanism of optically active compounds occurring by breaking a bond to the asymmetric carbon atom. 4 New interest in the configurational inversion was initiated by Hoffmann, Alder, and Wilcox in 1970 in their discussion of the MO’s for planar tetracoordinate carbon. 5