A Divergent Strategy for Site-Selective Radical Disulfuration of Carboxylic Acids with Trisulfide-1,1-Dioxides

The direct conversion of carboxylic acids into disulfides is described. The approach employs oxidative photocatalysis for base-promoted decarboxylation of the substrate, which yields an alkyl radical that reacts with a trisulfide dioxide through homolytic substitution. The trisulfide dioxides are easily prepared by a newly described approach. 1 degrees, 2 degrees, and 3 degrees carboxylic acids with varied substitution are good substrates, including amino acids and substrates with highly activated C-H bonds. Trisulfide dioxides are also used to achieve the gamma-C(sp(3))-H disulfuration of amides through a radical relay sequence. In both reactions, the sulfonyl radical that results from substitution propagates the reaction. Factors governing the selectivity of substitution at S2 versus S3 of the trisulfide dioxides have been explored.

Automated summary

The study describes a method for the direct conversion of carboxylic acids into disulfides, utilizing oxidative photocatalysis to promote decarboxylation. It was found that trisulfide dioxides can be easily prepared and used for various types of carboxylic acid substrates, including amino acids and substrates with activated C-H bonds. Additionally, the method was applied to the disulfuration reaction of amides.