反应详情

To a solution of tert-butyl (2R,3R,4S)-5-azido-3-(tert-butyldimethylsilyloxy)-1-hydroxy-4-methylpentan-2-ylcarbamate (1.0 equiv.) in pyridine (0.2 M) was added MsCl (1.3 equiv.) followed by DMAP (catalytic amount) at 0° C. The mixture was stirred at that temperature for 1 hour. The solution was diluted with ether and ethyl acetate (4:1), washed with aq. NaHSO4, sat. NaHCO3, brine, dried over magnesium sulfate, filtered, and concentrated. The residue was purified by silica gel column chromatography eluting with ethyl acetate and hexanes (1:3) to give (2R,3R,4S)-5-azido-2-(tert-butoxycarbonylamino)-3-(tert-butyldimethylsilyloxy)-4-methylpentyl methanesulfonate as the major isomer (5:2) in 90% yield. LC/MS=367.3 (M+H-Boc), Rt=0.81 min (Frac 65%-95% method).

1. washwashed with aq. NaHSO4, sat. NaHCO3, brine
2. dry with materialdried over magnesium sulfate
3. filtrationfiltered
4. concentrationconcentrated
5. customThe residue was purified by silica gel column chromatography
6. washeluting with ethyl acetate and hexanes (1:3)