NHC‐Catalyzed Asymmetric Intramolecular [3+2] Annulations of Cyclohexadienone‐Tethered Ynals

Abstract NHC‐Catalyzed enantioselective conversion of ynals remains challenging through nucleophilic NHC‐allenolate intermediates. Herein, we present an NHC‐catalyzed highly asymmetric intramolecular [3+2] annulation of cyclohexadienone‐tethered ynals. This reaction enables a rapid and efficient construction of 6,5,5‐tricyclic frameworks bearing three contiguous stereocenters in excellent enantioselectivities. Additionally, the synthetic utility is elaborated through a gram‐scale experiment and several downstream transformations.