Meyer-Eppler Georg, Sure Rebecca, Schneider Andreas, Schnakenburg Gregor, Grimme Stefan, Lützen Arne
Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn , Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany.
J Org Chem. 2014 Jul 18;79(14):6679-87. doi: 10.1021/jo501212t. Epub 2014 Jul 7.
Despite the fact that functionalized planar chiral [2.2]paracyclophanes have received a lot of attention, the chemistry of pseudo-meta 4,15-distubstituted [2.2]paracyclophanes is largely unexplored. This is mainly due to the fact that the 4,5-dibromo-functionalized [2.2]paracyclophane is much less prone to halogen-metal exchange reactions than its constitutional pseudo-ortho or pseudo-para isomers. Here, we give an account of an efficient protocol to achieve this, which allows the synthesis of a broad variety of 4,15-disubstituted [2.2]paracyclophanes. Furthermore, we were able to resolve several of the racemic compounds via chiral HPLC and assign the absolute configurations of the isolated enantiomers by X-ray diffraction and/or by the comparison of calculated and measured CD-spectra.
尽管功能化的平面手性[2.2]对环芳烷已受到广泛关注，但假间位4,15-二取代[2.2]对环芳烷的化学性质在很大程度上仍未被探索。这主要是因为4,5-二溴功能化的[2.2]对环芳烷比其结构上的假邻位或假对位异构体更不容易发生卤代金属交换反应。在此，我们阐述了一种实现此目标的有效方法，该方法能够合成多种4,15-二取代[2.2]对环芳烷。此外，我们能够通过手性高效液相色谱法拆分几种外消旋化合物，并通过X射线衍射和/或通过比较计算的和实测的圆二色光谱来确定分离出的对映体的绝对构型。
