Transition‐Metal‐Free Difunctionalization of Sulfur Nucleophiles

Efficient protocols for accessing iodo‐substituted diaryl and aryl(vinyl) sulfides have been developed using iodonium salts as reactive electrophilic arylation and vinylation reagents. The reactions take place under transition‐metal‐free conditions, employing odorless and convenient sulfur reagents. A wide variety of functional groups are tolerated in the S‐diarylation, enabling the regioselective late‐stage application of several heterocycles and drug molecules under mild reaction conditions. A novel S‐difunctionalization pathway was discovered using vinyliodonium salts, which proceeds under additive‐free reaction conditions and grants excellent stereoselectivity in the synthesis of aryl(vinyl) sulfides. A one‐pot strategy combining transition‐metal‐free diarylation and subsequent reduction provided facile access to electron‐rich thioanilines and a direct synthesis of a potential drug candidate derivative. The retained iodo group allows a wide array of further synthetic transformations. Mechanistic insights were elucidated by isolating the key intermediate, and the relevant energy profile was substantiated by DFT calculations.