A copper-catalyzed three component reaction of aryl acetylene, sulfonyl azide and enaminone to form iminolactone via 6π electrocyclization.

We developed a copper-catalyzed three component reaction of aryl acetylene, enaminone and sulfonyl azide to construct iminolactone via a cascade process involving copper-catalyzed alkyne-azide cycloaddition (CuAAC), Michael addition of metalated ketenimine followed by elimination and 6π electrocyclization.