Cascade One‐Pot Synthesis of Orange‐Red‐Fluorescent Polycyclic Cinnolino[2, 3‐f]phenanthridin‐9‐ium Salts by Palladium(II)‐Catalyzed C−H Bond Activation of 2‐Azobiaryl Compounds and Alkenes. (19th November 2019) - Jayakumar, Jayachandran
Abstract: Quaternary ammonium salts were synthesized in moderate to good yields through double oxidative C−H bond activation on azobenzenes. The mechanism of the highly regioselective reaction of 2‐azobiaryls with alkenes to give orange‐red‐fluorescent cinnolino[2, 3‐ f ]phenanthridin‐9‐ium salts and 15 H ‐cinnolino[2, 3‐ f ]phenanthridin‐9‐ium‐10‐ide is proposed to involve ortho C−H olefination of the 2‐azobiaryl compound with the alkene, intramolecular aza‐Michael addition, concerted metalation–deprotonation (CMD), reductive elimination, and oxidation. Abstract : Beflügelt : Orange‐rote fluoreszierende Cinnolino[2, 3‐ f ]phenanthridin‐9‐iumsalze wurden mit hoher Regioselektivität aus 2‐Azobiarylen und Alkenen durch Palladium(II)‐katalysierte C‐H‐Aktivierung unter milden Reaktionsbedingungen synthetisiert (siehe Schema). Die so erhaltenen quartären Ammoniumsalze zeigten starke Fluoreszenzemissionsmaxima bei 575–620 nm mit großen Bandbreiten.