Synthesis of Si-Bridgehead Polycyclic Aromatic Hydrocarbons via Ru-Catalyzed Double Annulation of Secondary Silanes with Internal Alkynes

The incorporation of silicon into the bridgehead positions of polycyclic aromatic hydrocarbons is challenging because it requires successive annulations and formation of multiple Si-C bonds. This study presents a Si-H directed double annulation method for synthesizing silicon-embedded benzo[<i>cd</i>]pyrene and coronene. Single-crystal X-ray diffraction analysis revealed relatively reduced planarity and bond alteration in the resulting products. DFT calculations indicated that the HOMOs and LUMOs are delocalized across the fused-ring systems, consistent with the observed bathochromic shifts in the UV-vis absorption and photoluminescence spectra.