A convenient synthesis of quinolizinium salts through Rh(III) or Ru(II)-catalyzed C-H bond activation of 2-alkenylpyridines

An efficient synthesis of quinolizinium salts from 2-vinylpyridines and alkynes via Rh(III) or Ru(II)-catalyzed C-H activation and annulation reaction is described. A possible mechanism involving pyridine assisted vinylic ortho-C-H activation, alkyne insertion and reductive elimination is proposed.