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机械学研究铜催化不对称的基的化

Yumeng Xi¹, John F Hartwig¹

¹Division of Chemical Sciences, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California , Berkeley, California 94720, United States.

Journal of the American Chemical Society

|August 9, 2017

概括

这项研究揭示了铜催化不对称水力钻井中的关键催化中间体. DTBM-SEGPHOS连接物通过一种甲铜中间体实现了高效的维尼拉烯化,而SEGPHOS则导致一种不活性的铜化物.

科学领域:

有机金属化学有机金属化学
不对称的催化剂.
合成方法论合成方法论

背景情况:

铜催化不对称的化是合成性有机化合物的关键反应.
了解机械路径和识别催化中间体对于优化这些反应至关重要.
连接物选择显著影响了铜催化转换中的催化剂活性和选择性.

研究的目的:

阐明维尼拉烯和内部烯的铜催化不对称化过程的机械细节.
识别和描述关键的催化中间体和静止状态.
研究不同素配体 (DTBM-SEGPHOS和SEGPHOS) 在催化循环中的作用.

主要方法:

使用DTBM-SEGPHOS和SEGPHOS连接体进行了详细的机制研究.
通过NMR光谱学和X射线晶体学对催化中间体的表征.
使用密度函数理论 (DFT) 来理解选择性起源的计算分析.

主要成果:

在DTBM-SEGPHOS中,一种甲铜 () 复合物被确定为静态和催化中间体,用于维尼拉水电化.
维尼拉烯的营业额限制步骤是用皮纳科尔博兰 (HBpin) 化乙铜复合物.
对于内部烯,DTBM-SEGPHOS结合的二二酸盐复合物是静止状态,烯插入铜化物作为速度限制的步骤.
这种SEGPHOS连接体导致了触媒不活性的二度铜化物种.
DFT的计算显示,铜结合碳和环移位的负荷决定了区域选择性和反应速率.

结论:

这项研究提供了对铜催化不对称的化工艺的详细机制理解,突出了连接物结构的重要性.
通过精确定义的中间体,DTBM-SEGPHOS促进了高效的催化,而SEGPHOS导致了失活.
计算洞察力将电子因子与观察到的区域和enantioselectivity相关联,指导未来的催化剂设计.

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