Synthesis and Properties of Tribenzocarbazoles via an Acid-Promoted Retro (2+2)-Cycloaddition of Azapropellanes

We describe herein the development of a new method to synthesize tribenzocarbazoles via an acid-promoted retro (2+2)-cycloaddition of azapropellanes, which were prepared by potassium hexamethyldisilazide (KHMDS)-promoted (2+2)-cycloaddition. The tribenzocarbazoles showed strong fluorescence both in solution and the solid state. The structural, electronic, and optical properties of the synthetic tribenzocarbazoles are also described.