Li Shaofeng, Feng Shijie, Zhou Yali, Liu Chao, Chen Bo, Xing Xiangyou
Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China.
J Am Chem Soc. 2023 Oct 18;145(41):22745-22752. doi: 10.1021/jacs.3c08420. Epub 2023 Oct 6.
Asymmetric olefin metathesis is a powerful strategy for stereocontrolled synthesis that allows the formation of chiral elements in conjunction with carbon-carbon double bonds. Here, we report a new series of cyclometalated stereogenic-at-Ru catalysts that enable highly efficient asymmetric ring opening/cross-metathesis (AROCM) and asymmetric ring-closing metathesis (ARCM) reactions. Single enantiomers of these catalysts with either right-handed or left-handed configurations at the Ru center can be easily accessed via highly stereoselective C-H bond activation-based cyclometalation. Right-handed chiral Ru catalysts enabled the - and enantioselective AROCM of a wide range of norbornenes and terminal alkenes, generating densely functionalized cyclopentanes with excellent stereo- and enantioselectivities (99:1 /, up to 99% ee). Left-handed chiral Ru catalysts enabled the facile ARCM of sterically unhindered, all-terminal prochiral trienes, which had not been achieved by previous Ru catalysts, providing simple cyclic ethers and amides with tertiary or quaternary carbon stereocenters with excellent enantioselectivities (up to 99% ee).
不对称烯烃复分解反应是立体控制合成的一种强大策略，它能够在形成碳 - 碳双键的同时构建手性结构单元。在此，我们报道了一系列新型的环金属化钌手性催化剂，这些催化剂能够实现高效的不对称开环/交叉复分解反应（AROCM）和不对称关环复分解反应（ARCM）。通过基于高度立体选择性的C - H键活化的环金属化反应，可以轻松获得在钌中心具有右手或左手构型的这些催化剂的单一对映体。右手性钌催化剂能够实现多种降冰片烯和末端烯烃的高对映选择性AROCM反应，生成具有优异立体选择性和对映选择性（99:1 /，高达99% ee）的密集官能化环戊烷。左手性钌催化剂能够实现空间位阻较小的全末端前手性三烯的简便ARCM反应，这是以前的钌催化剂无法实现的，能够提供具有优异对映选择性（高达99% ee）的带有叔碳或季碳立体中心的简单环状醚和酰胺。
