Gold(III)-Catalyzed Formal [3 + 2] Annulations of N-Acyl Sulfilimines with Ynamides for the Synthesis of 4-Aminooxazoles

A gold-catalyzed formal 1,3-dipolar [3 + 2] annulation using readily accessible N-acyl sulfilimines and ynamides is reported. This reaction includes the cleavage of a N-S bond and subsequent C-O bond formation. In total, 30 oxazole derivatives bearing diverse functionalities could be prepared in 43-98% yield from the corresponding sulfilimines and ynamides.