Modular Synthesis of BN-Embedded Phenyl- or Naphthyl-Fused Dibenzofulvene Derivatives via Palladium-Catalyzed Domino Reaction of BN-Naphthalene

The metal-catalyzed intramolecular alkyne cyclization reaction was developed for the efficient construction of BN-embedded aryl-fused dibenzofulvene derivatives. Utilizing palladium-catalyzed intramolecular alkyne cyclization of BN-naphthalene 1, followed by Suzuki coupling or reductive Heck coupling reactions, a series of phenyl- and naphthyl-fused dibenzofulvene derivatives with different substituents (2 and 3) were first synthesized. X-ray diffraction analysis confirmed the structures of compounds 2g and 2s, the latter of which exhibits a significantly twisted helical conformation resembling helicenes. Computational studies suggest the delocalization of π electrons over the BN-embedded polycyclic skeleton.