Synthesis and structure of conjugated molecules with the benzofulvene core

A general method to synthesize conjugated molecules with a benzofulvene core is reported. Up to four conjugated substituents have been introduced via a three-step sequence including (1) synthesis of 1,2-bis(arylethynyl)- benzenes; (2) exo-dig electrophilic cyclization promoted by iodine; and (3) cross-coupling reaction of the resulting bisiodobenzofulvenes with organoboron, organotin, or ethynyl derivatives under Pd catalysis. Structural aspects of the new compounds are discussed.