Smiles Rearrangement

Abstract

The Smiles rearrangement is an intramolecular nucleophilic substitution attacking on an aromatic system bearing an activating electron‐withdrawing group at ortho ‐ or para ‐position to the reaction center connected to a heteroatom. This rearrangement is accompanied by the migration of an aromatic ring from the heteroatom binding to the reaction center to a more nucleophilic heteroatom. It has been found that a moderate electron‐withdrawing group such as chloro and alkoxide can accelerate this rearrangement. On the other hand, the steric hindrance arising from a substituent at a particular position in the aromatic ring may facilitate the Smiles rearrangement. The solvent, such as THF has been found to give positive effect and increase the rate of the Smiles rearrangement. This reaction has been extensively modified by the use of different tethers as well as various reaction conditions.