Catalytic asymmetric synthesis of inherently chiral tricyclic diazepinones: Access to (+)-telenzepine

Molecules with inherent chirality, which stems from their overall conformation rather than local stereogenic centers, present a notable synthetic challenge. This is especially evident for bioactive, saddle-shaped tricyclic diazepinones, whose conformational flexibility has hampered asymmetric synthesis. Herein, we address this issue through a late-stage organocatalytic asymmetric N-H alkylation strategy. By introducing torsional strain via strategic N-H functionalization, we lock the molecular chiral conformation and enable direct synthesis of diverse enantioenriched tricyclic diazepinones from prochiral precursors. The modular nature of this approach is demonstrated through the kinetic resolution of racemic substrates, as well as in, to our knowledge, the first enantioselective synthesis and absolute configuration confirmation of the drug molecule (+)-telenzepine.