Dynamic NMR Study of the Rotation around “Biphenyl-Type” Bonds in Polycyclic Sulfoxides
作者:Samuel Braverman、Yossi Zafrani、Hugo E. Gottlieb
DOI:10.1021/jo010947z
日期:2002.5.1
on the synthesis and the products of both symmetrical and asymmetrical starting materials. We also measure, by NMR techniques, the rotation rate of the side chain for several such polycyclic sulfoxides. The barriers for this process, which is similar to a biphenyl rotation, are very strongly dependent on the nature of the substrate, ranging between <7 and 21.0 kcal.mol(-1) for sulfoxides with two five-membered
在最近的一篇论文中,我们报道了双炔丙基亚砜在碱催化下的重排,最终导致具有不饱和环状取代基(如环己烯基或苯基)的多环产物。由于空间限制,后者的位置大致垂直于三环核,并且在大多数情况下,可以在基态下观察到两个旋转异构体。在目前的工作中,我们报告了对称和不对称起始原料的合成及其产物。我们还通过NMR技术测量了几种此类多环亚砜的侧链旋转速率。此过程的障碍类似于联苯旋转,非常强烈地取决于基质的性质,范围在<7至21.0 kcal之间。带有两个五元环和两个七元环的亚砜的mol(-1)。可以通过分子力学计算成功地模拟这些势垒,并讨论了过渡态的几何形状。