<i>meta</i> -Sulfonylation of Pyridines from Sulfur Dioxide with Dearomatized Pyridines as Redox-Active Substrates

-sulfonylation of pyridines via a dearomatization and rearomatization strategy from sulfur dioxide with thianthrenium salts as radical precursors. Mechanistic studies indicated that oxazino-pyridine substrates serve as redox-active substrates that quench the excited photocatalyst.