A Gold-Catalyzed Acid-Assisted Regioselective Cyclization for the Synthesis of Polysubstituted Oxazoles

Abstract

Polysubstituted oxazole derivatives are obtained through a regioselective gold-catalyzed reaction of α-alkynylamides and alkynoates in the presence of nitriles. The intermediary obtained gold carbenes are generated by alkyne oxidation with a pyridine N-oxide. Acidic conditions ensure that only one of the two carbonyl oxygen atoms in these intermediates selectively cyclizes to the products in excellent yields.