On the Mechanism of Bifunctional Squaramide-Catalyzed Organocatalytic Michael Addition: A Protonated Catalyst as an Oxyanion Hole
作者:Bianka Kótai、György Kardos、Andrea Hamza、Viktor Farkas、Imre Pápai、Tibor Soós
DOI:10.1002/chem.201304553
日期:2014.5.5
bifunctional pathways that involve electrophile activation by the protonated amine group of the catalyst. However, some of the minor product isomers are also accessible through alternative reaction routes. Structural analysis of transition states points to the structural invariance of certain fragments of the transition state, such as the protonated catalyst and the anionic fragment of approaching reactants
进行了一项联合实验理论研究,研究了1,3-二氧代亲核试剂与硝基苯乙烯之间的双官能方胺-胺催化的迈克尔加成反应,以了解双官能有机催化活化的性质。对于这种高立体选择性反应,三先前提出的机械方案的严重C 检查了碳键形成步骤。因此,最主要的立体异构产物的形成通过涉及催化剂的质子化胺基团亲电活化的双功能途径之一是最合理的。然而,一些次要产物异构体也可通过替代反应途径获得。过渡态的结构分析指向某些过渡态片段的结构不变性,例如质子化催化剂和接近反应物的阴离子片段。我们的拓扑分析为双功能非共价有机催化提供了更深入的见解和更一般的理解。