N‐Heterocyclic Carbene‐Catalyzed [2+2+2] Annulation of Allenoates with Trifluoromethylketones

Abstract In contrast with the reported phosphine‐ and DABCO‐catalyzed [3+2] and [2+2] annulation of allenoates with trifluoromethylketone, the [2+2+2] annulation of allenoates and two molecules of trifluoromethylketone was found under the condition of N ‐heterocyclic carbene catalysis.