Palladium-Catalyzed Modular Synthesis of Thiophene-Fused Polycyclic Aromatics via Sequential C–H Activation

A palladium-catalyzed Catellani-type [2+2+2] annulation reaction of aryl iodides, bromothiophenes, and norbornadiene, which proceeds via a tandem Heck coupling/double C-H bond activation and retro-Diels-Alder pathway to access thiophene-fused polyaromatics, is reported. The key feature of this protocol represents a NBD/NBE retaining annulation.