Jiang Xinhang, Li En, Chen Jiean, Huang Yong
State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China and Shenzhen Public Platform of Drug Screening and Preclinical Evaluation, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Pingshan Translational Medicine Center, Shenzhen Bay Laboratory, Shenzhen, 518055, China and Shenzhen Public Platform of Drug Screening and Preclinical Evaluation, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Chem Commun (Camb). 2021 Jan 26;57(6):729-732. doi: 10.1039/d0cc07264h.
The geometric configuration of olefin products is often driven by thermodynamic control in synthesis. Methods enabling switching of cis/trans selectivity are rare. Recently, photosensitized approaches have emerged as a powerful tool for accomplishing this task. In this report, we report an in situ isomerization of an N-heterocyclic carbene (NHC)-bound intermediate by a photo-induced energy transfer process that leads to selective access of chiral allylic fluorides with a cis-olefin geometry. In the absence of a photocatalyst or light, the reaction proceeds smoothly to give (E)-olefin products, while the (Z)-isomer can be obtained under photosensitizing conditions. Preliminary mechanistic experiments suggest that an energy transfer process might be operative.
烯烃产物的几何构型在合成中通常受热力学控制。能够切换顺式/反式选择性的方法很少见。最近，光敏方法已成为完成这项任务的有力工具。在本报告中，我们报道了一种通过光诱导能量转移过程实现的N-杂环卡宾（NHC）结合中间体的原位异构化，该过程导致选择性获得具有顺式烯烃几何构型的手性烯丙基氟化物。在没有光催化剂或光的情况下，反应顺利进行，生成（E）-烯烃产物，而（Z）-异构体可以在光敏条件下获得。初步的机理实验表明能量转移过程可能起作用。
