Late-stage Modification of Coumarins via Aryliodonium Intramolecular Aryl Migration

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 pi-expanded coumarin derivatives. Furthermore, the photophysical properties of the coumarin compounds were examined for their potential in material science.