Late‐stage Modification of Coumarins via Aryliodonium Intramolecular Aryl Migration

Abstract A novel approach concerning modification of coumarins with hypervalent iodine reagents was developed by an intramolecular aryl migration. The approach features new coumarin‐based aryliodonium salts for the formation of C(sp2)−O bond under transition metal‐free conditions. As a result, a family of functional coumarins bearing reactive C−I bond were produced efficiently. The products as useful synthons were demonstrated with coupling reactions for π‐expanded coumarin derivatives. Furthermore, the photophysical properties of the coumarin compounds were examined for their potential in material science.