Au(III)-Catalyzed Stereoselective Synthesis of Alkylidene β-Diketones

Significance

A variety of propargyl esters were efficiently converted into alkylidene β-diketones in the presence of a Au(III)/pyridine-2-carboxylate catalyst. Excellent yields were reported, as well as short reaction times (<1 day, but generally 0.4-5 h). E/Z ratios of the products were fair to good when propargyl acetates or benzoates were used, but were excellent with propargyl acrylates or carbamates. Mechanistic studies support the formation of an intermediate allenyl ester, as they are converted into the products under the reaction conditions.