Negishi Coupling for Highly Selective Syntheses of Allenes via Ligand Effect and Mechanistic Study via SAESI‐MS/MS
作者:Yangguangyan Zheng、Bukeyan Miao、Anni Qin、Junzhe Xiao、Qi Liu、Gen Li、Li Zhang、Fang Zhang、Yinlong Guo、Shengming Ma
DOI:10.1002/cjoc.201900322
日期:2019.10
Assisted Electrospray Ionization Mass Spectrometry) has been applied to successfully capture the highly reactive organometallic intermediates, which show the different coordination behaviors of Pd with SPhos or Gorlos‐Phos as the ligand in the catalytic cycle. In addition, the different reactivities of Int 1 and Int 2 towards the formation of the final allene products have been demonstrated via SAESI‐MS/MS
在过渡金属催化的反应中,β-H的消除是一个固有的问题。我们在此描述了一个有趣的Et 2 Zn分别充当乙基提供者或H提供者的配体效应:通过应用SPhos或Gorlos-Phos作为配体,已成功在相应的Negishi偶联反应中控制了β-H的消除,从而提供了不同的聚预取代的异戊烯,收率高,选择性好。SAESI-MS(š olvent甲ssisted é lectrospray我onization中号屁股小号光谱法)已成功地捕获了高反应性的有机金属中间体,这些中间体在催化循环中显示出Pd与SPhos或Gorlos-Phos作为配体的不同配位行为。此外,通过SAESI-MS / MS实验证明了Int 1和Int 2对最终丙二烯产物形成的不同反应性。这些质谱研究可视化了Negishi偶联反应的整个催化循环,同时很好地解释了所观察到的反应性和选择性。