Palladium-catalyzed decarboxylation [2 + 2 + 2] annulation approach to chromone-containing polycyclic compounds

A variety of chromone-containing polycyclic compounds are efficiently generated via Pd-catalyzed decarboxylation [2 + 2 + 2] annulation of 3-iodochromones, bridged olefins and o-bromobenzoic acids, in which o -bromobenzoic acids were employed as the electrophilic aryl units.