Mechanistic analysis of an asymmetric palladium-catalyzed conjugate addition of arylboronic acids to β-substituted cyclic enones.
Mechanistic analysis of an asymmetric palladium-catalyzed conjugate addition of arylboronic acids to β-substituted cyclic enones.
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DOI：
10.1039/c4sc03337j
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发表时间：
2015-03
期刊：
影响因子：
8.4
通讯作者：
Zare RN
中科院分区：
文献类型：
--
作者：
Boeser CL;Holder JC;Taylor BL;Houk KN;Stoltz BM;Zare RN
研究了钯催化芳基硼酸与烯酮底物的不对称共轭加成反应。解吸电喷雾电离耦合质谱用于识别催化循环的中间体，并描绘底物反应性的差异。我们的研究结果提供了证据的催化循环进行通过形成的芳基钯（ii）阳离子，随后形成的芳基钯-烯酮络合物，并最终形成新的C-C键。在正离子和负离子模式下的反应监测显示，4-碘苯基硼酸在反应条件下形成相对稳定的三聚体物质。钯催化的共轭加成反应的机理的洞察，获得了使用解吸电喷雾电离耦合质谱。
An asymmetric palladium-catalyzed conjugate addition reaction of arylboronic acids to enone substrates was investigated mechanistically. Desorption electrospray ionization coupled to mass spectrometry was used to identify intermediates of the catalytic cycle and delineate differences in substrate reactivity. Our findings provide evidence for the catalytic cycle proceeding through formation of an arylpalladium(ii) cation, subsequent formation of an arylpalladium–enone complex, and, ultimately, formation of the new C–C bond. Reaction monitoring in both positive and negative ion modes revealed that 4-iodophenylboronic acid formed a relatively stable trimeric species under the reaction conditions. Mechanistic insight into a Pd-catalyzed conjugate addition reaction was gained using desorption electrospray ionization coupled to mass spectrometry.