Visible-light-mediated synthesis of 3-arylsulfonylated thioflavones using an in situ activation strategy

We have developed a visible-light-mediated synthesis of 3-arylsulfonylated thioflavones using an in situ-activation strategy. The reaction proceeds through a one-pot, three-component pathway, without the need for sensitive or harsh reaction conditions. Organic photocatalysts were employed to generate aryl radicals more efficiently from aryl diazonium salts generated in situ. This method enables the synthesis of 3-arylsulfonylated thioflavones from aryl amines and methylthiolated alkynones, utilizing potassium metabisulfite as an inexpensive source of sulfur dioxide. The resulting products were obtained under mild reaction conditions. This approach provides an efficient alternative pathway for synthesizing thioflavone derivatives, which are prevalent among various bioactive compounds.