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

The synthesis of 4-(trifluoromethyl)-2,3-dihydrothiazoles from alpha-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 alpha-enolic dithioesters.