Frontispiece: Direct and Enantioselective Synthesis of N−H‐Free 1,5‐Benzodiazepin‐2‐ones by an N‐Heterocyclic Carbene Catalyzed [3+4] Annulation Reaction

The 1,5-benzodiazepin-2-one heterocyclic motif is a privileged structure frequently found in numerous natural products and synthetic compounds with diverse biological activities. An N-heterocyclic carbene-catalyzed formal [3+4] annulation of α,β-unsaturated acylazoliums with protecting group-free aryl 1,2-diamines is reported by T. Lu, D. Du et al. in their Full Paper on page 2103 ff., for a direct and highly enantioselective synthesis of 4-aryl N−H-free 1,5-benzodiazepin-2-ones. The protocol is also scalable and the desired products can easily undergo subsequent derivatizations.