Closed-Loop Sulfur Dioxide Utilization in Photocatalytic Smiles Rearrangement.

Radical-mediated Smiles rearrangement has been established as a robust methodology for forming C-C bonds via intramolecular radical cyclization and cleavage under mild conditions. Herein, we present an unprecedented closed-loop sulfur dioxide utilization in a photocatalytic Smiles rearrangement. This methodology enables efficient access to sulfone derivatives through an economical and environmentally benign protocol, exhibiting excellent compatibility with diverse substrates. Mechanistic investigations reveal that both alkyl and sulfonyl radicals act as crucial intermediates in this reaction.