Asymmetric Construction of Lactam Scaffolds Catalyzed by N‐heterocyclic Carbenes

Lactams with four, five, six and seven‐membered heterocycles represent important motifs in a wide range of natural products and medical molecules. Thus, great efforts are devoted to synthesize lactam derivatives for enhanced bioactivity and therapeutic potential. Recently, asymmetric catalysis by N‐heterocyclic carbenes (NHCs) has emerged as a powerful tool to construct enantiomerically enriched stereocenters of carbo‐ and heterocycles from simple materials without additional separation processes. This review focuses on the developments in NHCs‐catalyzed asymmetric synthesis strategies toward the construction of β ‐, γ ‐, δ ‐ and ε ‐lactams via annulation reactions. This work provides a comparative overview of reaction efficiencies, substrate scopes, and enantioselectivities across different NHC scaffolds and activation modes, highlighting key trends and limitations. Furthermore, where possible, mechanistic insights are correlated with observed stereochemical outcomes. Finally, special attention is given to underdeveloped areas, including the synthesis of β ‐ and ε ‐lactams, cooperative NHC/transition metal catalysis, and enantioselective radical cycloadditions.