A Unified Approach to Quinolizinium Cations and Related Systems by Ring-Closing Metathesis^†

The first example of an olefin ring-closing metathesis reaction on cationic heteroaromatic systems is described. Dihydroquinolizinium cations and a variety of related cationic systems are synthesized in an efficient approach from N-alkenyl α-vinyl azinium salts using Grubbs' catalysts.