Synthesis of Quinolizinium-Type Heteroaromatics via a Carbene Intermediate.

An efficient synthesis of quinolizinium-type heteroaromatics by Pt(II)-catalyzed cyclization of 2-arylpyridine propargyl alcohol has been developed. The presence of a protic acid is crucial for the success of the reaction. Mechanistic studies disclosed that the reaction proceeds via a platinum-carbene intermediate. Additionally, the fluorescence properties of the synthesized heteroaromatics were investigated to provide perspectives for potential applications.