反应详情

温度

5 °C

23 g (80 mmol) of the compound from Example 29A are dissolved in 80 ml of anhydrous tetrahydrofuran and cooled to 5° C. Over a period of 15 min, 21 g (176 mmol) of 9-borabicyclo[3.3.1]nonane (0.5M solution in tetrahydrofuran) are added. Cooling is removed, and the mixture is stirred at room temperature for another 2 h. The mixture is then again cooled to 5° C., and 400 ml of 1N aqueous sodium hydroxide solution are added. After the addition has ended, 81 ml of 30% strength hydrogen peroxide solution are added a little at a time at this temperature. After dilution with 500 ml of ethyl acetate, the mixture is washed with 32 ml of 40% strength sodium bisulphite solution to destroy the peroxides. The organic phase is separated off, and the aqueous phase is extracted four times with ethyl acetate. The combined organic phases are washed with saturated sodium chloride solution, dried over magnesium sulphate and, after filtration, concentrated to dryness under reduced pressure. The residue is chromatographed on silica gel using a gradient of cyclohexane and ethyl acetate. The product-containing fractions are combined and concentrated to dryness under reduced pressure. This gives 20 g (77% of theory) of the desired product.

1. temperatureCooling
2. customis removed
3. temperatureThe mixture is then again cooled to 5° C.
4. addition400 ml of 1N aqueous sodium hydroxide solution are added
5. additionAfter the addition
6. addition81 ml of 30% strength hydrogen peroxide solution are added a little at a time at this temperature
7. washAfter dilution with 500 ml of ethyl acetate, the mixture is washed with 32 ml of 40% strength sodium bisulphite solution
8. customto destroy the peroxides
9. customThe organic phase is separated off
10. extractionthe aqueous phase is extracted four times with ethyl acetate
11. washThe combined organic phases are washed with saturated sodium chloride solution
12. dry with materialdried over magnesium sulphate
13. filtrationafter filtration
14. concentrationconcentrated to dryness under reduced pressure
15. customThe residue is chromatographed on silica gel using a gradient of cyclohexane and ethyl acetate
16. concentrationconcentrated to dryness under reduced pressure