A visible-light photocatalytic thiolation of aryl, heteroaryl and vinyl iodides

Abstract

The general catalytic synthesis of aryl and vinyl thioethers from readily available halides remains a challenge. Herein we report a unified method for the thiolation of aryl and vinyl iodides with dialkyl disulfides using visible light photoredox catalysis. A range of thioether products bearing diverse functional groups can be accessed in high yield and with excellent chemoselectivity. We demonstrate the versatility of this method through the expedient synthesis of a family of thioether-rich natural products. A detailed investigation of the photocatalytic mechanism is presented from both steady-state and time-resolved luminescent quenching as well as transient absorption spectroscopy experiments.

Visible Light as the Key for the Formation of Carbon–Sulfur Bonds in Sulfones, Thioethers, and Sulfonamides: An Update

“…Aryl and vinyl sulfides 178 were obtained by Polyzos (Scheme 61) via the thiolation of aryl and vinyl iodides 176 with dialkyl disulfides 177, as the source of thiyl radicals, using visible-light photoredox catalysis. 86 This procedure afforded a range of sulfides 178 bearing diverse functional groups in moderate to good yields and with excellent chemoselectivity. The versatility of the method was demon-strated by its application to a family of natural products bearing multiple sulfide functionalities.…”

DABCO‐promoted Diaryl Thioether Formation by Metal‐catalyzed Coupling of Sodium Sulfinates and Aryl Iodides

“…We extended the screen to other amine bases and found that DABCO significantly improve the product yield to 55% (Table , entries 5–7). Effectively, Polyzos and co‐workers reported a visible light photocatalytic method for thioether formation from aryl iodides and disulfide, and DABCO served as single electron donor in the photocatalytic cycle . Subsequently, DABCO was chosen as the base and various catalysts including commonly used iron catalysts (Table , entries 10–12), nickel catalysts (Table , entries 13–15) and palladium catalysts (Table , entries 16–18) were screened.…”

Copper-Catalyzed Methylthiolation of Aryl Iodides and Bromides with Dimethyl Disulfide in Water

“…unified method for the thiolation of aryl or vinyl iodides with dimethyl disulfide by using the visible-light photocatalyst fac-Ir(ppy) 3 has been reported by Polyzos's group. 30 Nevertheless, each of the procedures discussed above entails various disadvantages, such as the need to use expensive metals, stoichiometric amounts of transition-metal sources, appropriate ligands, prefunctionalized substrates, organic peroxides, environmentally damaging organic solvents, or harsh reaction conditions. Undoubtedly, an efficient and environmentally benign synthetic procedure would still be much appreciated.…”