Noncovalent interactions between a lone pair of electrons and π systems can be categorized into two types based on the nature of π systems. Lone pair−π(C═O) interactions with π systems of unsaturated, polarized bonds are primarily attributed to orbital interactions, whereas lone pair−π(Ar) interactions with π systems of aromatic functional groups result from electrostatic attractions (for electron-deficient aryls) or dispersion attractions and Pauli repulsions (for electron-rich/neutral aryls). Unlike well-established noncovalent interactions, lone pair−π interactions have been comparatively underappreciated or less used to influence reaction outcomes. This review emphasizes experimental and computational studies aimed at integrating lone pair−π interactions into the design of catalytic systems and utilizing these interactions to regulate the reactivity and selectivity of chemical transformations. The role of lone pair−π interactions is highlighted in the stabilization or destabilization of transition states and ground-state binding. Examples influenced by lone pair−π interactions with both unsaturated, polarized bonds and aromatic rings as π systems are included. At variance with previous reviews, the present review is not structured according to the physical origin of particular classes of lone pair−π interactions but is divided into chapters according to ways in which lone pair−π interactions affect kinetics and/or selectivity of reactions.

中文翻译：

---

有机反应中的孤对 −π 相互作用


孤对电子和π系统之间的非共价相互作用可以根据π系统的性质分为两种类型。孤对-π（C═O） 与不饱和极化键π系统的相互作用主要归因于轨道相互作用，而孤对-π（Ar） 与芳香族官能团π系统的相互作用是由静电吸引（对于缺电子的芳基）或分散吸引和泡利排斥（对于富电子/中性芳基）引起的。与公认的非共价相互作用不同，孤对-π 相互作用相对被低估或较少用于影响反应结果。本综述强调了旨在将孤对-π相互作用整合到催化系统设计中的实验和计算研究，并利用这些相互作用来调节化学转化的反应性和选择性。孤对-π 相互作用的作用在过渡态和基态结合的稳定化或不稳定性中得到强调。包括受孤对 −π 与不饱和极化键和芳香环相互作用影响的示例，作为π系统。与以前的综述不同，本综述不是根据特定类别的孤对 - π 相互作用的物理起源进行构建的，而是根据孤对 - π 相互作用影响动力学和/或反应选择性的方式分为几章。