Regio‐, Stereoselective, Aerobic and Metal‐Free Synthesis of Z‐Vinyl Sulfides: One‐pot Hydroiodination of Internal Alkynes and in situ Sulfenylations

Abstract

A novel, metal‐free, air‐ and moisture‐compatible one‐pot tandem protocol for the regio‐ and stereoselective synthesis of Z‐vinyl sulfides (achieving yields up to 99%), is reported. This straightforward and efficient process combines the selective hydroiodination of internal alkynes, promoted by the eutectic mixture choline iodide (ChI)/p‐TsOH (1:1) under mild, bench‐type conditions (without the need for toxic molecular HI), with a subsequent sulfenylation step of the in situ‐generated vinyl iodides. This final step is compatible with aromatic, heteroaromatic and aliphatic thiols. Notably, the methodology addresses a longstanding challenge by enabling the selective formation of Markovnikov products with Z‐configuration in the thiolation of secondary propiolamides. It also avoids volatile organic solvents and is easily scalable to gram quantities, offering significant advantages for synthetic applications.