Palladium-Catalyzed Carbonylative Sonogashira/Annulation Reaction: Synthesis of Indolo[1,2-]isoquinolines

A palladium-catalyzed carbonylative Sonogashira/annulation reaction for the synthesis of indolo[1,2-]isoquinolines has been developed. Tetracyclic 6/5/6/6 indoline skeletons were synthesized in moderate to good yields from easily available 2-bromo--(2-iodophenyl)benzamides and terminal alkynes. Notably, this efficient methodology established three C-C bonds and a C-N bond through a one-step transformation and provided a new method for the synthesis of indolo[1,2-]isoquinoline derivatives.