反应详情

To a clear solution of Example 34 (10 mmol) in tetrahydrofuran (60 ml) at 0° C., n-BuMgcl (2M solution in THF, 25 ml, 50 mmol) is added over 10 minutes. After stirring for an additional 20 minutes, the ice bath is removed and the solution is stirred for 2 hours. The reaction mixture is recooled to 0° C. and triethylborane (1M solution in THF, 60 ml, 60 mmol) is added. After stirring for 1 hour, the reaction is heated to reflux for 72 hours. The reaction mixture is cooled to room temperature and treated with aqueous sodium acetate (5.5 g in 22 ml water). After stirring for 5 minutes, solid hydroxylamine-O-sulfonic acid (5.5 g) is added and the mixture stirred for 24 hours. The reaction mixture is diluted with water and extracted with ether. The ethereal layer is dried over sodium sulfate, filtered and concentrated. The crude solid is chromatographed on silica gel using mixtures of hexane and isopropanol to give the desired product.

1. customthe ice bath is removed
2. stirringthe solution is stirred for 2 hours
3. customis recooled to 0° C.
4. stirringAfter stirring for 1 hour
5. temperaturethe reaction is heated
6. temperatureto reflux for 72 hours
7. stirringAfter stirring for 5 minutes
8. stirringthe mixture stirred for 24 hours
9. extractionextracted with ether
10. dry with materialThe ethereal layer is dried over sodium sulfate
11. filtrationfiltered
12. concentrationconcentrated
13. customThe crude solid is chromatographed on silica gel using mixtures of hexane and isopropanol