Non-electronic activation of aromatic frameworks by steric repulsion between peri-substituents

Abstract

Distortion of coplanarity has been known as one of the activation methods for planar aromatic rings, and a great deal of effort has been devoted to experimental and computational studies. However, there is no study on systematic evaluation for distortion by steric repulsion between substituents. Inspired by this fact, several studies have focused on non-electronic activation caused by steric interactions between peri-substituents. These studies indicated systematically and quantitatively how varying the bulkiness of substituents affects the distortion and the resulting dearomatization, and changes in reactivity due to the distortion (e.g., non-electronic activation) were also compared. Furthermore, this concept is applied to 1,8-dihalonaphthalenes to afford unsymmetrical products via the halogen dance reaction.