Pd(OAc)2-catalyzed intramolecular dehydrogenative cross-coupling reaction between tertiary enamides, which were derived from the condensation of 2-arylethylamines and methyl o-acetylbenzoate, and arenes enabled synthesis of 7,8-dihydro-5H-benzo[4,5]azepino[2,1-a]-isoindol-5-one derivatives under mild conditions. The synthetic method was applied in the total synthesis of aporhoeadane alkaloids palmanine, lennoxamine, and chilenamine in only three or four steps.