A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand
A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand
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钴(I)催化芳基卤化物胺化的机理研究：金属和配体的影响
DOI：
10.1021/acs.inorgchem.2c02385
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发表时间：
2022
影响因子：
4.6
通讯作者：
Lung Wa Chung
中科院分区：
文献类型：
--
作者：
Jialing Lan;Tonghuan Zhang;Yuhong Yang;Xin Li;Lung Wa Chung
过渡金属催化芳基卤化物胺化反应是合成药用化合物、有机功能材料和农用化学品的有效途径。采用系统的离散傅立叶变换研究了以（PPh3）3CoCl为预催化剂，以Co(I)催化LiN(SiMe3)2胺化芳基卤化物的机理。我们的计算结果表明，在三重态下，最有利的解离协同c - i激活途径包括(a)一个pph3配体的解离，(b) c - i键的协同氧化加成（OA）， (c)金属转化，(d)第二个pph3配体的（可选）解离，(e)形成c - n键的还原消除（RE），以及(f)配体交换以再生活性物质。相比之下，结合协调的OA、自由基、SH2/SN2、单电子转移（SET）和σ-键的转化途径由于其较高的势垒或不利的反应自由能而不太有利。进一步研究了不同金属（Rh和Ir）作为催化剂中心的影响，发现需要更高的反应障碍，因为它们较强的m - pph3键不利于解离。这些结果突出了地球上丰富的Co催化剂在解离途径中的优势。总的来说，我们的研究为过渡金属催化胺化提供了更深入的机制见解，并指导了高效co基催化剂的设计。
Transition-metal-catalyzed amination of aryl halides is a useful approach for the synthesis of medicinal compounds, organic functional materials, and agrochemical compounds. A systematic DFT study has been performed to investigate the mechanism of the Co(I)-catalyzed amination of aryl halides by LiN(SiMe3)2using (PPh3)3CoCl as the precatalyst. Our computational results suggest that the most favorable dissociative concerted C–I activation pathway in a triplet state consists of (a) dissociation of one PPh3ligand, (b) concerted oxidative addition (OA) of the C–I bond, (c) transmetalation, (d) (optional) dissociation of the second PPh3ligand, (e) C–N bond-forming reductive elimination (RE), and (f) ligand exchange to regenerate the active species. Comparatively, the associative concerted OA, radical, SH2/SN2, single electron transfer (SET), and σ-bond metathesis pathways should be less favorable due to their higher barriers or unfavorable reaction free energies. The effects of different metals (Rh and Ir) as centers in the catalyst were further examined and found to require higher reaction barriers, due to unfavorable dissociation of their stronger M–PPh3bonds. These results highlight an advantage of the earth-abundant Co catalysts for the dissociative pathway(s). Overall, our study offers deeper mechanistic insights for the transition-metal-catalyzed amination and guides the design for efficient Co-based catalysts.