Enantioselective Synthesis of Fully Benzenoid Single and Double Carbohelicenes via Gold-Catalyzed Intramolecular Hydroarylation.

The enantioselective synthesis of fully benzenoid single and double carbo[6]helicenes has been achieved via the gold-catalyzed intramolecular hydroarylation. The single crystal of the racemic double carbo[6]helicene consists of unique layer structures like timbers with halving joints in the woodworking. Furthermore, the double carbo[6]helicenes exhibited relatively large CPL activities among chiral small organic molecules.