Suresh Rahul, Orbach Noam, Marek Ilan
Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa, 3200009, Israel.
Angew Chem Int Ed Engl. 2024 Jul 29;63(31):e202407602. doi: 10.1002/anie.202407602. Epub 2024 Jun 27.
Neighboring group participation, the assistance of non-conjugated electrons to a reaction center, is a fundamental phenomenon in chemistry. In the framework of nucleophilic substitution reactions, neighboring group participation is known to cause rate acceleration, first order kinetics (S1), and retention of configuration. The latter phenomenon is a result of double inversion: the first one when the neighboring group displaces the leaving group, and the second when a nucleophile substitutes the neighboring group. This powerful control of stereoretention has been widely used in organic synthesis for more than a century. However, neighboring group participation may also lead to inversion of configuration, a phenomenon which is often overlooked. Herein, we review this unique mode of stereoinversion, dividing the relevant reactions into three classes with the aim to introduce a fresh perspective on the different modes of stereoinversion via neighboring group participation as well as the factors that control this stereochemical outcome.
邻基参与，即非共轭电子对反应中心的协助，是化学中的一种基本现象。在亲核取代反应的框架内，邻基参与已知会导致反应速率加快、一级动力学（S1）以及构型保持。后一种现象是双重翻转的结果：第一次是邻基取代离去基团时，第二次是亲核试剂取代邻基时。这种对立体构型保持的强大控制在有机合成中已经广泛应用了一个多世纪。然而，邻基参与也可能导致构型翻转，这一现象常常被忽视。在此，我们综述这种独特的立体构型翻转模式，将相关反应分为三类，旨在为通过邻基参与实现的不同立体构型翻转模式以及控制这种立体化学结果的因素引入一个全新的视角。
