To a solution of {(S)-1-[(2S,3S)-1-(4-acetyl-benzoyl)-2-methyl-4-oxo-2,3,4,5-tetrahydro-1H-benzo[b][1,4]diazepin-3-ylcarbamoyl]-ethyl}-methyl-carbamic acid tert-butyl ester (60 mg, 0.115 mmol) in N,N-dimethylformamide (1.0 mL) was added cesium carbonate (94 mg, 0.287 mmol), 5-bromo-1-chloromethyl-2-methoxy-naphthalene (39.3 mg, 0.138 mmol) and sodium iodide (17.2 mg, 0.115 mmol) and the reaction was stirred for 2 h. The reaction mixture was diluted with water (10 ml) and extracted with ethyl acetate (2×15 mL). The organic layers were combined, washed with brine (1×10 mL), dried over sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by chromatography over silica gel gradient eluted with 10 to 70% v/v ethyl acetate hexanes to give {(S)-1-[(2S,3S)-1-(4-acetyl-benzoyl)-5-(5-bromo-2-methoxy-naphthalen-1-ylmethyl)-2-methyl-4-oxo-2,3,4,5-tetrahydro-1H-benzo[b][1,4]diazepin-3-ylcarbamoyl]-ethyl}-methyl-carbamic acid tert-butyl ester (40 mg, 45%).
