Gold-Catalyzed ( <i>n</i> + 4) ( <i>n</i> = 5, 6) High-Order Dipolar Annulation of Alkynylcyclopropane Ketones: Unified Synthesis of Medium-Sized Diazaheterocycles

We developed a gold-catalyzed ( n + 4) ( n = 5, 6) high-order dipolar annulation between imidazolidines or hexahydropyrimidines and alkynylcyclopropane ketones. This method provides a modular, atom-efficient strategy for accessing two libraries of synthetically challenging medium-sized diazaheterocycles in moderate to good yields under mild conditions. Control experiments on chirality transfer support a dominant stereospecific S N 2 pathway that proceeds via a cyclopropyl oxonium-containing vinyl gold intermediate. Moreover, asymmetric catalysis, including kinetic resolution and dynamic kinetic asymmetric transformation, to enantioenriched products has been realized, highlighting the synthetic potential of this methodology.