Triethyloxonium tetrafluoroborate → [(S)-1-(6-Fluoro-1-pyridin-2-yl-1H-benzoimidazol-2-yl)ethyl]carbamic acid tert-butyl ester

Participants

Reaction Steps

To a solution of (S)-Boc-alaninamide (1.5 g, 7.9 mmol) in anhydrous THF (20 mL) was added triethyloxonium tetrafluoroborate (1.6 g, 8.3 mmol) in one portion under a nitrogen atmosphere. The resulting mixture was left to stir at RT for 2 h. The volatiles were removed in vacuo and the resulting residue redissolved in absolute EtOH (20 mL). To the mixture was added 4-fluoro-N2-pyridin-2-yl-benzene-1,2-diamine (1.0 g, 4.9 mmol) and the mixture stirred at 75° C. for 16 h. The volatiles were removed in vacuo and the resulting residue partitioned between DCM and a saturated aqueous solution of NaHCO3. The aqueous phase was further extracted with DCM and the combined organic fractions washed with water, dried (MgSO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 0-40% EtOAc in cHex) to afford the title compound as an orange oil (1.6 g, 92%). LCMS (Method B): RT 3.21 min [M+H]+ 357.0.

Provenance & Evidence