Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Japan.
Research Center of Integrative Molecular Science (CIMoS), Institute for Molecular Science, Okazaki, Aichi, Japan.
Nat Commun. 2021 Mar 5;12(1):1473. doi: 10.1038/s41467-021-21720-4.
The E/Z stereocontrol in a C=C bond is a fundamental issue in olefin synthesis. Although the thermodynamically more stable E geometry is readily addressable by thermal Z to E geometric isomerization through equilibrium, it has remained difficult to undergo thermal geometric isomerization to the reverse E to Z direction in a selective manner, because it requires kinetic trapping of Z-isomer with injection of chemical energy. Here we report that a dinuclear Pd-Pd complex mediates selective isomerization of E-1,3-diene to its Z-isomer without photoirradiation, where kinetic trapping is achieved through rational sequences of dinuclear elementary steps. The chemical energy required for the E to Z isomerization can be injected from an organic conjugate reaction through sharing of common Pd species.
C=C 键的 E/Z 立体控制是烯烃合成中的一个基本问题。尽管热力学上更稳定的 E 几何形状可以通过平衡热 Z 到 E 几何异构体化轻易地实现，但很难以选择性的方式经历热立体异构化为相反的 E 到 Z 方向，因为它需要用化学能来动力学捕获 Z-异构体。在这里，我们报告说，双核 Pd-Pd 配合物在没有光照射的情况下介导 E-1,3-二烯的选择性异构化为其 Z-异构体，其中通过双核基本步骤的合理顺序实现了动力学捕获。E 到 Z 异构体化所需的化学能可以通过共享常见的 Pd 物种从有机共轭反应中注入。
