One-Pot Regio- and Diastereoselective Gold-Catalyzed Propargylation of in Situ Activated Chromones and Consecutive Cyclization

Herein, we report a gold-catalyzed propargylation of chromone derivatives by propargylsilanes. Chromones are synergistically activated by the silylium cation resulting from the gold activation of the propargylsilane. The reaction exclusively occurs at the C2-position of the chromone, and a single diastereoisomer is formed. Computational studies performed on the reaction mechanism rationalize the formation of the preferred diastereoisomer. Finally, a dual consecutive cascade reaction based on different gold catalysts enables the formation of complex tricyclic compounds.