Synthesis of <i>N</i>-Aryl-4-trifluoromethylthiazol-2-amines via Insertion/Annulation of Trifluoromethylimidoyl Sulfoxonium Ylides with Sodium Thiocyanate

An efficient <i>p</i>-TsOH-mediated insertion of sodium thiocyanate into trifluoromethylimidoyl sulfoxonium ylides has been reported, affording annulated <i>N</i>-aryl-4-trifluoromethylthiazol-2-amines in 42-84% yields in a one-pot manner. This protocol encompasses a variety of trifluoromethylimidoyl sulfoxonium ylides with thiocyanate serving as the source of the "S-C═N" moiety of the thiazole ring. The versatile transformations of the resulting pharmacologically important <i>N</i>-aryl-4-trifluoromethylthiazol-2-amines were also demonstrated.