An NHC-Catalyzed Desulfonylative Smiles Rearrangement of Pyrrole and Indole Carboxaldehydes.

The use of catalysis methods to enable Smiles rearrangement opens up new substrate classes for arylation under mild conditions. Here, we describe an N-heterocyclic carbene (NHC) catalysis system that accesses indole and pyrrole aldehyde substrates in a desulfonylative Smiles process. The reaction proceeds under mild, transition-metal-free conditions and captures acyl anion reactivity for the synthesis of a diverse array of 2-aroyl indoles and pyrroles from readily available sulfonamide starting materials.