Mechanistic investigations of alcohol silylation with isothiourea catalysts
Mechanistic investigations of alcohol silylation with isothiourea catalysts
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异硫脲催化剂醇硅烷化反应的机理研究
DOI：
10.1039/d1ob01732b
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发表时间：
2021
影响因子：
3.2
通讯作者：
Wiskur, Sheryl L.
中科院分区：
文献类型：
--
作者：
Redden, Brandon K.;Clark, Robert W.;Gong, Ziyuan;Rahman, Md. Mamdudur;Peryshkov, Dmitry V.;Wiskur, Sheryl L.
采用反应进度动力学分析方法，研究了异硫脲催化醇类不对称硅基化反应的反应机理。这些反应是由Wiskur基团开发的，并使用三苯基氯化硅和手性异硫脲催化剂对醇进行硅烷化。虽然大多数反应组分(催化剂、胺基、醇)的顺序与预期一致，但氯化硅的顺序被确定为更高的顺序。这表明催化剂和硅氯之间是一种多步骤机制，第二个等量的硅氯协助反应中间体的形成，从而导致速率决定步骤。通过添加添加剂和考察氯化硅烷的变化，了解了该反应的催化剂平衡，为进一步的反应发展提供了途径。
The mechanism of the asymmetric silylation of alcohols with isothiourea catalysts was studied by employing reaction progress kinetic analysis. These reactions were developed by the Wiskur group, and use triphenyl silyl chloride and chiral isothiourea catalysts to silylate the alcohols. While the order of most reaction components was as expected (catalyst, amine base, alcohol), the silyl chloride was determined to be a higher order. This suggested a multistep mechanism between the catalyst and silyl chloride, with the second equivalent of silyl chloride assisting in the formation of the reactive intermediate leading to the rate-determining step. Through the addition of additives and investigating changes in the silyl chloride, an understanding of the catalyst equilibrium emerged for this reaction and provided pathways for further reaction development.