反应详情

A solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-20-hydroxy-20-methylpregna-5,7,16-triene (67.7 mg, 0.118 mmol), sodium hydride (60% in oil, 40.0 mg, 1.00 mmol) and 1-bromo-2,3-epoxy-3-methylbutane (100 mg, 0.606 mmol) in tetrahydrofuran (1 ml) was refluxed under heating for 1.5 hours. To the thus obtained reaction solution, was added 1.0M L-SELECTRIDE/tetrahydrofuran solution (1.2 ml, 1.2 mmol) at room temperature, followed by stirring at the same temperature for 12 hours. After cooling the reaction solution with ice, a 3N aqueous sodium hydroxide solution and then hydrogen peroxide solution were added to the reaction solution. Immediately after the addition, the mixture was diluted with ethyl acetate and washed with water and saturated brine. The organic layer was dried over anhydrous magnesium sulfate and evaporated to remove the solvent under reduced pressure; the thus obtained residue was purified by preparative thin layer chromatography (2 sheets (each 0.5 mm thickness), hexane:ethyl acetate=15:1, developed once) to give the titled compound (72.5 mg, 93%) as a colorless oil.

1. temperatureunder heating for 1.5 hours
2. customTo the thus obtained reaction solution
3. temperatureAfter cooling the reaction solution with ice
4. additionImmediately after the addition
5. washwashed with water and saturated brine
6. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
7. customevaporated
8. customto remove the solvent under reduced pressure
9. customthe thus obtained residue was purified by preparative thin layer chromatography (2 sheets (each 0.5 mm thickness), hexane