A comprehensive understanding of carbon-carbon bond formation by alkyne migratory insertion into manganacycles.
A comprehensive understanding of carbon-carbon bond formation by alkyne migratory insertion into manganacycles.
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DOI：
10.1039/d2sc02562k
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发表时间：
2022-08-31
期刊：
影响因子：
8.4
通讯作者：
Lynam, Jason M.
中科院分区：
文献类型：
--
作者：
Hammarback, L. Anders;Eastwood, Jonathan B.;Burden, Thomas J.;Pearce, Callum J.;Clark, Ian P.;Towrie, Michael;Robinson, Alan;Fairlamb, Ian J. S.;Lynam, Jason M.
迁移插入（MI）是过渡金属催化C-C键和C-X键形成的重要过程之一。在这项工作中，提出了一个全面的MI模型，直接观察的基础上参与耦合的炔与环化配体的状态，增加了从计算化学的洞察力。时间分辨光谱表明配合物[Mn（C^N）（CO）4]（C^N =环化配体）的光解导致CO配体的超快解离。在炔的甲苯溶液中进行实验导致溶剂络合物fac-[Mn（C^N）（甲苯）（CO）3]的初始形成。溶剂取代得到η2-炔配合物fac-[Mn（C^N）（η2-R1 C2 R2）（CO）3]，它将不饱和配体MI到Mn-C键中。这些数据允许溶剂取代的二级速率常数和C-C键形成的一级速率常数的依赖性被确定。本文系统地研究了炔和C^N配体对该反应的影响。实验数据使MI反应的计算模型的发展，这表明，金属和新生的C-C键之间的协同相互作用控制反应的速率和区域化学的结果。时间分辨光谱方法能够观察到发生在8个数量级的多步反应，包括溶剂络合物的形成，配体取代和两个连续的C-C键形成步骤。时间分辨光谱学和计算化学为炔迁移插入提供了统一的模型，这是过渡金属催化的C-C和C-X键形成的重要过程。
Migratory insertion (MI) is one of the most important processes underpinning the transition metal-catalysed formation of C–C and C–X bonds. In this work, a comprehensive model of MI is presented, based on the direct observation of the states involved in the coupling of alkynes with cyclometallated ligands, augmented with insight from computational chemistry. Time-resolved spectroscopy demonstrates that photolysis of complexes [Mn(C^N)(CO)4] (C^N = cyclometalated ligand) results in ultra-fast dissociation of a CO ligand. Performing the experiment in a toluene solution of an alkyne results in the initial formation of a solvent complex fac-[Mn(C^N)(toluene)(CO)3]. Solvent substitution gives an η2-alkyne complex fac-[Mn(C^N)(η2-R1C2R2)(CO)3] which undergoes MI of the unsaturated ligand into the Mn–C bond. These data allowed for the dependence of second order rate constants for solvent substitution and first order rate constants for C–C bond formation to be determined. A systematic investigation into the influence of the alkyne and C^N ligand on this process is reported. The experimental data enabled the development of a computational model for the MI reaction which demonstrated that a synergic interaction between the metal and the nascent C–C bond controls both the rate and regiochemical outcome of the reaction. The time-resolved spectroscopic method enabled the observation of a multi-step reaction occurring over 8 orders of magnitude in time, including the formation of solvent complexes, ligand substitution and two sequential C–C bond formation steps. Time-resolved spectroscopy and computational chemistry have informed a unified model of alkyne migratory insertion, an important processes underpinning the transition metal-catalysed formation of C–C and C–X bonds.
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影响因子：
2.8
作者：
GRIGSBY, WJ;MAIN, L;NICHOLSON, BK
通讯作者：
NICHOLSON, BK
影响因子：
15
作者：
Hammarback, L. Anders;Robinson, Alan;Fairlamb, Ian J. S.
通讯作者：
Fairlamb, Ian J. S.
铱催化烯烃氢芳基化配体控制的线性与支链选择性的机制和起源
影响因子：
12.9
作者：
Huang, Genping;Liu, Peng
通讯作者：
Liu, Peng
影响因子：
15
作者：
Hammarback, L. Anders;Aucott, Benjamin J.;Lynam, Jason M.
通讯作者：
Lynam, Jason M.
影响因子：
3.6
作者：
LIEBESKIND, LS;GASDASKA, JR;TREMONT, SJ
通讯作者：
TREMONT, SJ