Facile Synthesis of Azahelicenes and Diaza[8]circulenes through the Intramolecular Scholl Reaction

Abstract Carbazole‐based aza[7]helicenes and hetero[9]helicenes were successfully obtained via the intramolecular Scholl reaction of 3,6‐bis(biphenyl‐2‐yl)carbazole congeners, while the reaction of 3,6‐bis(naphthylphenyl)‐appended carbazole gave a triple helicene via an unexpected simultaneous double aryl rearrangement. DFT calculations suggested that the rearrangement proceeded via an arenium cation intermediate. In addition, the reaction of methoxy‐appended substrate gave an azahepta[8]circulene via the concurrent C−C bond formation. These helical dyes showed circularly polarized luminescence. The azahepta[8]circulene was further transformed into deeply saddle‐distorted dibenzodiaza[8]circulenes as the first example of its solution‐based synthesis and unambiguous structural determination.