Tropos, Nevertheless Conformationally Stable Biphenyl Derivatives
Tropos, Nevertheless Conformationally Stable Biphenyl Derivatives
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DOI：
10.1002/ejoc.201300087
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发表时间：
2013-04-01
影响因子：
2.8
通讯作者：
Blaeser, Dieter
中科院分区：
文献类型：
--
作者：
Haberhauer, Gebhard;Tepper, Christina;Blaeser, Dieter
在邻位和邻位上具有小取代基的联苯衍生物被称为tropos。由于连接两个苯基单元的CC键周围的低旋转势垒，仅分离一个构象异构体是不可能的;因此它们是构象不稳定的。使用DFT计算，我们能够表明，使用合适的肽桥连单元，联苯系统可以变得构象稳定。这种稳定化应该与邻位和邻位上的取代基类型无关。一些建议的联苯衍生物的成功合成和研究在溶液和固体状态。VT-NMR、2D-NMR和CD谱表明所有联苯衍生物均为P构象。的P构象的偏好被证实的联苯衍生物在固态的结构。
Biphenyl derivatives with small substituents in the ortho and ortho positions are called tropos. Due to the low rotation barrier around the CC bond connecting the two phenyl units, the isolation of only one conformer is not possible; thus they are conformationally unstable. Using DFT calculations, we were able to show that using a suitable peptidic bridging unit, biphenyl systems can become conformationally stable. This stabilization should be independent of the type of substituent in the ortho and ortho positions. Some of the proposed biphenyl derivatives were successfully synthesized and studied in solution and solid state. The recorded VT-NMR, 2D-NMR and CD spectra show that all biphenyl derivatives exhibit the P conformation. The preference for the P conformation is confirmed by the structure of a biphenyl derivative in solid state.