Rhodium(III)‐Catalyzed Heteroannulations of 3‐Sulfolene Derivatives through C(sp2)−H Activation: Access to Pyridine ortho‐Quinodimethane Precursors

Abstract

AbstractHydroxamates derived from 3‐sulfolene‐3‐carboxylic acid can be involved in intra‐ and intermolecular rhodium(III)‐catalyzed heteroannulations with alkynes proceeding through C(sp2)−H bond activation. These transformations allow for a straightforward access to diversely substituted pyridones, and to pyridines fused to a sulfolene ring after functional group transformations. Subsequent cheletropic elimination of sulfur dioxide can be achieved under microwave irradiation to generate pyridine ortho‐quinodimethanes. These results demonstrate that the scope of rhodium(III)‐catalyzed C(sp2)−H functionalizations can be extended to sulfolenes, a yet unexplored class of alkenes in these latter transformations, thereby affording access to valuable classes of heterocyclic products.