medicinal chemistry and organic synthesis is known. An efficient route to γ-keto sulfones through a metal-free reaction of cyclopropanols, sulfur dioxide and electron-deficient olefins is achieved. This reaction proceeds smoothly under mild conditions without the need of catalyst, oxidant or additive. A plausible mechanism is proposed, which undergoes through γ-keto sulfinate intermediate generated
An efficient synthesis of quinolizinium salts from 2-vinylpyridines and alkynes via Rh(III) or Ru(II)-catalyzed CâH activation and annulation reaction is described. A possible mechanism involving pyridine assisted vinylic ortho-CâH activation, alkyne insertion and reductive elimination is proposed.