Photo-catalyzed sequential dearomatization/carboxylation of benzyl o-halogenated aryl ether with CO2 leading to spirocyclic carboxylic acids

Photo-catalyzed tandem dearomatization/carboxylation of benzyl o-halogenated aryl ether with CO2 was achieved, which affords spirocyclic carboxylic acids under mild conditions. The reaction has good functional group tolerance with high yields. Mechanism studies indicate that the transformation was realized via intramolecular radical addition and nucleophilic addition.