Synthesis of 4‐(Trifluoromethyl)‐2,3‐Dihydrothiazoles from α‐Enolic Dithioesters and Imidoyl Sulfoxonium Ylides

The synthesis of 4‐(trifluoromethyl)‐2,3‐dihydrothiazoles from α‐enolic dithioesters and imidoyl sulfoxonium ylides has been achieved under thermal conditions. This transformation is catalyst‐free, additive‐free, and operationally simple, and it proceeds via a formal insertion of alkenyl S−H generated in situ from dithioesters into ylides followed by an intramolecular annulation. This approach further expands the synthetic application of two versatile sulfur‐containing building blocks of fluorinated imidoyl sulfoxonium ylides and α‐enolic dithioesters.