Stabilizing Effect of Pre-equilibria: A Trifluoromethyl Complex as a CF 2 Reservoir in Catalytic Olefin Difluorocarbenation
Stabilizing Effect of Pre-equilibria: A Trifluoromethyl Complex as a CF 2 Reservoir in Catalytic Olefin Difluorocarbenation
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预平衡的稳定作用：三氟甲基配合物作为催化烯烃二氟碳化反应中的 CF 2 储层
DOI：
10.1021/acscatal.1c05959
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发表时间：
2022
期刊：
影响因子：
12.9
通讯作者：
Hyvl, Jakub
中科院分区：
文献类型：
--
作者：
Louis-Goff, Thomas;Trinh, Huu Vinh;Chen, Eileen;Rheingold, Arnold L.;Ehm, Christian;Hyvl, Jakub
介绍了一种有效的催化烯烃二氟卡宾化反应生成1，1-二氟环丙烷的方法。该催化剂是一种有机铋络合物，使用TMS-CF 3作为化学计量的二氟卡宾源。我们证明了这种反应的可行性和鲁棒性，在广泛的烯烃和炔烃，包括缺电子烯烃，产生相应的1，1-二氟环丙烷和1，1-二氟环丙烯。易于从反应混合物中回收催化剂是该方法的另一个有吸引力的特征。深入的实验和理论研究表明，关键的二氟卡宾生成步骤是通过铋的非氧化还原同步机制在吸能预平衡中生成高活性的游离CF2.可逆的二氟卡宾生成-以及因此低浓度的活性物质-导致高选择性，同时最小化CF2-重组副反应。
An efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMS-CF3as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In-depth experimental and theoretical studies show that the key difluorocarbene-generating step proceeds through a bismuth nonredox synchronous mechanism generating highly reactive free CF2in an endergonic pre-equilibrium. The reversible difluorocarbene generation─and thus low concentration of active species─leads to high selectivity while minimizing CF2-recombination side reactions.