反应详情

温度

-75 °C

A 3-L three-necked flask equipped with a mechanical stirrer, thermometer, addition funnel, and Ar-inlet tube was charged with 91.9 g (160 mmol) of (1α,3β,17Z)-dimethyl[[1-[(triethylsilyl)oxy]pregna-5,7,17(20)-trien-3-yl]oxy](1,1,2-trimethylpropyl)silane, 62.8 mL (240 mmol) of 4-[[(1,1-dimethylethyl)dimethylsilyl]oxy-4-methyl-2-pentynal, and 480 mL of hexane. After cooling to -75° C., 480 mL (480 mmol) of a 1M dimethylaluminum chloride solution in hexane was added over 1 hr. After stirring at -75° C. for 1.5 hr., 66.9 mL (480 mmol) of triethylamine was added followed by 147 mL of ammonium hydroxide over 5 min. After 5 min, the cold-bath was removed, and the mixture was stirred for 2 hr (Gas evolved). Then, 147 g of powder Na2SO4 was added, and the stirring was continued for 30 min. The solid was removed by filtration and washed with a total of 720 mL of hexane. The combined hexane solutions were washed with 480 mL of 95% methanol. The methanol layer was extracted with 240 mL of hexane. The combined hexane solutions were dried over Na2SO4 and concentrated. The residue was then dried under high vacuum overnight to give 153 g (overweight) of crude (1α,3β)-25-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-3-[[dimethyl(1,1,2-trimethylpropyl)silyl]oxy]-1-[(triethylsilyl)oxy]cholesta-5,7,16-trien-23-yn-22-ol as a brown viscous oil.

1. customA 3-L three-necked flask equipped with a mechanical stirrer
2. additionthermometer, addition funnel
3. waitAfter 5 min
4. customthe cold-bath was removed
5. stirringthe mixture was stirred for 2 hr (Gas evolved)
6. additionThen, 147 g of powder Na2SO4 was added
7. waitthe stirring was continued for 30 min
8. customThe solid was removed by filtration
9. washwashed with a total of 720 mL of hexane
10. washThe combined hexane solutions were washed with 480 mL of 95% methanol
11. extractionThe methanol layer was extracted with 240 mL of hexane
12. dry with materialThe combined hexane solutions were dried over Na2SO4
13. concentrationconcentrated
14. customThe residue was then dried under high vacuum overnight