Substrate scope for the synthesis of 1,4-benzodiazepines^a.

^aReaction conditions: 1 (0.3 mmol), 2 (0.3 mmol), and Cs₂CO₃ (0.3 mmol) in solvent HFIP (3.0 mL) at room temperature for 0.5 h, then the HFIP was removed under vacuum and added DMF (2.0 mL) to continue to react for 0.5 h. Isolated yield.