Regiodivergent and Stereoselective Hydrothiolation of Ynamides

We report a regiodivergent and stereoselective hydrothiolation of ynamides, enabling access to α- or β-aminovinyl sulfides with complete stereocontrol under mild and sustainable conditions. Notably, this study introduces the first example of the hydrogen-bond-mediated umpolung β-addition of ynamides, employing ionic liquids (ILs) as bifunctional hydrogen-bond activators. This conceptually distinct approach expands the reactivity of ynamides beyond canonical keteniminium pathways. Mechanistic insights, supported by spectroscopic studies, reveal dual electrophile-nucleophile activation via ILs. The method offers a broad substrate scope, high regio- and stereoselectivity, and synthetic utility toward complex molecules, including tetrasubstituted alkenes, benzothiophene derivatives, and AIE-active materials.