Disulfides are versatile catalysts. They can be photocatalysts, hydrogen atom transfer (HAT) catalysts, cocatalysts, or initiators in photocatalytic reactions. Under photoirradiation, organic disulfides can be easily cleaved into free thiyl radicals (RS•) and can reversibly add to unsaturated multiple bonds to catalyze a variety of functionalization reactions under mild conditions. In photoredox catalysis reactions, an excellent electron transfer ability and excellent radical properties also made these thiyl radicals powerful HAT catalysts. They have increasingly been proven useful in various types of organic photoreactions, such as cyclizations, anti-Markovnikov additions, aromatic olefin carbonylations, isomerizations, etc. They are a class of green, economic, mild, and chemoselective radical catalysts that deserve more attention. The present review highlights the recent progress in the field of disulfide-catalyzed and -cocatalyzed photocatalytic reactions for different reaction types.

A continuous-flow photocatalytic synthesis of the industrially important thiuram disulfides has been developed, utilizing O2 as the oxidant and Eosin Y as the photoredox catalyst.

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We report herein a general and efficient continuous flow‐based protocol for synthesizing thiophene‐2‐carboxylates starting from ketal‐functionalized β‐nitroacrylates. The protocol involves (i) a promoter‐free conjugate addition of thioacetic acid to β‐nitroacrylates, (ii) a base‐induced elimination of nitrous acid, and (iii) a final acid‐promoted domino cyclization‐aromatization process to afford the title targets. Thanks to the means of the flow chemistry and the use of solid supported systems, the three steps were combined in a whole flow chemical process, by which the products were isolated in good to excellent overall yields (38–88%).magnified image

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