Sereda Oksana, Tabassum Sobia, Wilhelm René
Clausthal University of Technology, Leibnizstr. 6, 38678 Clausthal-Zellerfeld, Germany.
Top Curr Chem. 2010;291:349-93. doi: 10.1007/978-3-642-02815-1_17.
Abstract The term Lewis acid catalysts generally refers to metal salts like aluminium chloride, titanium chloride and zinc chloride. Their application in asymmetric catalysis can be achieved by the addition of enantiopure ligands to these salts. However, not only metal centers can function as Lewis acids. Compounds containing carbenium, silyl or phosphonium cations display Lewis acid catalytic activity. In addition, hypervalent compounds based on phosphorus and silicon, inherit Lewis acidity. Furthermore, ionic liquids, organic salts with a melting point below 100 degrees C, have revealed the ability to catalyze a range of reactions either in substoichiometric amount or, if used as the reaction medium, in stoichiometric or even larger quantities. The ionic liquids can often be efficiently recovered. The catalytic activity of the ionic liquid is explained by the Lewis acidic nature of their cations. This review covers the survey of known classes of metal-free Lewis acids and their application in catalysis.
摘要 “路易斯酸催化剂” 一词通常指金属盐，如氯化铝、氯化钛和氯化锌。它们在不对称催化中的应用可通过向这些盐中添加对映体纯配体来实现。然而，不仅金属中心可作为路易斯酸发挥作用。含有碳正离子、硅离子或鏻离子的化合物具有路易斯酸催化活性。此外，基于磷和硅的高价化合物具有路易斯酸性。此外，离子液体，即熔点低于100摄氏度的有机盐，已显示出能够以亚化学计量的量催化一系列反应，或者，如果用作反应介质，则以化学计量甚至更大的量催化反应。离子液体通常可以有效地回收。离子液体的催化活性由其阳离子的路易斯酸性本质来解释。本综述涵盖了已知的无金属路易斯酸类别及其在催化中的应用。
