Gold-catalyzed synthesis of polycyclic enones from carbon tethered 1,3-enynyl carbonyls via tandem heteroenyne metathesis and Nazarov reaction

(Chemical Equation Presented) An efficient and general Au(III)-catalyzed tandem reaction, heteroenyne metathesis and Nazarov cyclization, of 1,3-enynyl ketones to produce fused tri- and tetracyclic enones has been developed. The products were formed with excellent regioselectivity of the double bond position and with very high diastereoselectivities. In this reaction, the Au(III) catalyst exhibits dual roles for activating both alkynes and carbonyls.