期刊
ORGANIC CHEMISTRY FRONTIERS
卷 10, 期 15, 页码 3766-3775出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/d3qo00575e
关键词
-
Homogeneous organometallic catalysts based on ancillary ligands have important applications in organic synthesis. In recent years, the introduction of multiple functional sites into the ancillary ligand represents a new direction for metal-ligand cooperation (MLC) catalyst design. A theoretical study is presented to illuminate the mechanistic preference in transfer hydrogenation of alkynes catalyzed by an MLC catalyst with multiple functional sites in the ancillary ligand.
Homogeneous organometallic catalysts based on ancillary ligands have important applications in organic synthesis. In recent years, the introduction of multiple functional sites into the ancillary ligand represents a new direction for metal-ligand cooperation (MLC) catalyst design. However, the involvement of multiple functional sites in the active species leads to complicated influence factors and uncertain reaction mechanisms. Herein, a theoretical study is presented to illuminate the mechanistic preference in transfer hydrogenation of alkynes catalyzed by an MLC catalyst with multiple functional sites in the ancillary ligand. The calculations reveal that the conventional M-L bond MLC mode possesses a high activation energy barrier (34.3 kcal mol(-1)). In contrast, the catalyst adopts an unusual MLC mode where the NEt2 group behaves as the non-innocent ligand and facilitates the transfer hydrogenation with a more accessible activation free energy barrier (22.6 kcal mol(-1)). Further theoretical analysis indicates that the hemilability of the NEt2 group increases the nucleophilicity of the Co(i) hydride complex during the insertion reaction and reduces the ring strain of the transition state in the proton transfer process. The flexible coordination modes of the catalyst avoid the unfavored steric repulsion, leading to the enhanced activation of the substrate from the cobalt center. Our study demonstrates the mechanistic diversity of the MLC catalyst with multiple ancillary ligand sites, which is anticipated to provide inspiration for future homogeneous catalyst design.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据