Carboranes as Aryl Mimetics in Catalysis: A Highly Active Zwitterionic NHC-Precatalyst
作者:Christoph Selg、Wilma Neumann、Peter Lönnecke、Evamarie Hey-Hawkins、Kirsten Zeitler
DOI:10.1002/chem.201700209
日期:2017.6.12
and control reactions. In the design of N heterocyclic carbene catalysts both electronic and steric nature of the nitrogen substituents play a crucial role. While hydrocarbon-based systems and especially aryl residues have considerably contributed to surmount multifaceted catalytic challenges, the unique properties of carborane moieties such as delocalized charge, potential planar chirality and their
现代催化利用基于芳基的相互作用来调节和控制反应。在N杂环卡宾催化剂的设计中,氮取代基的电子和空间性质都起着至关重要的作用。尽管基于烃的系统(尤其是芳基残基)在克服多方面的催化挑战方面做出了巨大贡献,但碳硼烷部分的独特性能(例如离域电荷,潜在的平面手性及其众所周知的热力学稳定性)为开发新型催化剂(同时使用这些催化剂)提供了前所未有的机会。芳基模拟物。我们在此报告了一种直接的合成路线,该路线是新颖的基于两性离子三唑鎓的带有7,8-二氨基甲酰基-十一碳六氢呋喃基取代基的N-杂环卡宾(NHC)预催化剂。该催化剂的优异活性及其广泛的适用性在各种有机催化转化中得到了证明。与已知的N-芳基NHC催化剂的性能比较提供了对该Nido-Carboanyl取代基的立体电子性质的初步了解。