Aziridine used as a vinylidene unit in palladium-catalyzed [2 + 2 + 1] domino annulation

A novel palladium-catalyzed three-component reaction of 3-iodochromones with bridged olefins and aziridine is described, which employs a [2 + 2 + 1] domino annulation strategy to produce chromone fused methylenecyclopentanes in moderate to good yields via a Heck coupling/C(sp2)–H activation/imine–enamine tautomerization/retro-aza-Michael addition sequence. Significantly, aziridine was used as a vinylidene unit by cleavage of two C–N bonds and was successfully introduced into the products for the first time.