Oxygen → tert-butyl ((5R,6S)-5-(2-fluoro-5-nitrophenyl)-6-(2-hydroxyethyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of tert-butyl ((5R,6S)-6-allyl-5-(2-fluoro-5-nitrophenyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate (250 mg, 0.532 mmol) (cis-isomer from Step 1) in DCM (4 ml) and MeOH (1.3 ml), was added sodium bicarbonate (89 mg, 1.065 mmol) and the mixture was cooled to −78° C. The resulting mixture was ozonolized for about 10 min or until analysis showed no starting material present. The stream of oxygen was passed through the solution for 5 min, then solid sodium borohydride (40.3 mg, 1.065 mmol) was added to the mixture. The flask was removed from the bath and allowed to reach RT and stirred for 30 min. The reaction was quenched with saturated NH4Cl solution (caution: there is evolution of gas), diluted with water to dissolve solids and extracted into EtOAc. The organic layer was washed with brine, dried over MgSO4, filtered and concentrated to afford tert-butyl ((5R,6S)-5-(2-fluoro-5-nitrophenyl)-6-(2-hydroxyethyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate which was used in the next step without further purification.

Provenance & Evidence