Azonia Aromatic Cations by Ring‐Closing Metathesis: Synthesis of Azaquinolizinium Cations

Abstract

AbstractA strategy based on a ring‐closing metathesis (RCM) reaction of pyridinium azadienes in the presence of the second generation Grubbs catalyst was employed as a new approach to synthesize the 1‐azaquinolizinium (pyrido[1,2‐a]pyrimidin‐5‐ium) heterocycle and some simple derivatives. This method was also successfully applied to the first reported synthesis of the benzo‐1‐azaquinolizinium (pyrimido[2,1‐a]isoquinolinium) cation by using the Hoveyda–Grubbs catalyst in Cl2CHCHCl2 at 130 °C.