The palladium-catalyzed annulation of 1,4-dienes by aryl halides bearing ortho-heteroatoms and carbanion-stabilizing groups affords monocyclic and bicyclic 6-membered ring heterocycles and carbocycles in high yields by a process involving arylpalladium formation and addition to the diene, palladium migration, and intramolecular pi-allylpalladium displacement.