反应详情

To a solution of tert-butyl (2S,3R)-1-cyclohexyl-3-hydroxybutan-2-ylcarbamate (0.44 g, 1.62 mmol) in dry CH2Cl2 (10 mL) was added Et3N (0.71 g, 7 mmol, 4 eq) at 0 to −5° C. A solution of methanesulfonyl chloride (0.8 g, 7 mmol, 2 eq) in dry CH2Cl2 (5 mL) was added dropwise at the same temperature. The mixture was allowed to warm to rt gradually. TLC showed that the starting material had disappeared. Water (30 mL) was added. The aqueous layer was extracted with CH2Cl2 (3×20 mL). The combined organic layers was washed with 10% aq citric acid, satd aq NaHCO3 and brine, then dried over Na2SO4, filtered and concentrated to give tert-butyl (2S,3R)-1-cyclohexyl-3-(methanesulfonyloxy)butan-2-yl-carbamate (0.46 g, 81%), which was used in the next step without purification.

1. extractionThe aqueous layer was extracted with CH2Cl2 (3×20 mL)
2. washThe combined organic layers was washed with 10% aq citric acid
3. dry with materialdried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated