1,8-Diazabicyclo(5.4.0)undec-7-ene → (4S)-4-azido-6-bromo-2-methyl-2-(trifluoromethyl)chroman

Participants

Reaction Steps

To a cooled (ice bath) solution of (4R)-6-bromo-2-methyl-2-(trifluoromethyl)chroman-4-ol (277 mg, 890 μmol) was added drop wise diphenylphosphoryl azide (249 μl, 1158 μmol). After stirring 20 min, 1,8-diazabicyclo(5.4.0)undec-7-ene (173 μl, 1158 μmol) was added drop wise. The reaction was stirred at the same temperature for 2 h, then stirred 15 h at ambient temperature. Water was added to quench the reaction. The resulted mixture was extracted with EtOAc. The organics were washed with brine, dried over Na2 SO4, filtered and concentrated. The residue was purified on a silica gel column (5-20% EtOAc/hexane) to afford the title compound. MS m/z: 308 (M−N2).

Provenance & Evidence