The preparation of a variety of tetracyclic ring systems by palladium(0)-catalyzed cyclization of 2-bromobenzyloxy-substituted coumarins and quinolones is described. The process has been found to be a viable method for regioselective synthesis of the corresponding products in very good to excellent yield.
Heck reaction - palladium(0) catalysis - tetracyclic ring system - regioselectivity