反应详情

N-Bromosuccinimide (7.6 g) was added to a solution of methyl 2-(tert-butyldimethylsilyloxy)-6-methylbenzoate (Intermediate 13, 11.9 g) in carbon tetrachloride (150 mL) and the mixture was stirred and heated to reflux. Azo-bis-isobutyronitrile (0.1 g) was added and the mixture was illuminated with a 500 W tungsten filament lamp for 2 hours. The mixture was cooled and left to stand overnight then filtered through a 25 g silica cartridge eluting with a mixture of ethyl acetate and pentane (20%). The eluent was evaporated to dryness and the residue was redissolved in carbon tetrachloride (150 mL) and N-bromosuccinimide (6.96 g) was added. The mixture was heated to reflux and azo-bis-isobutyronitrile (0.1 g) was added. The resultant mixture was illuminated with a 500 W tungsten filament lamp overnight. After cooling, the mixture was filtered and the solid was washed with pentane. The combined organic solutions were evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of TBME and pentane with a gradient of 0-10% to give methyl 2-bromomethyl-6-(tert-butyldimethylsilyloxy)benzoate (4.99 g) as a yellow oil.

1. temperatureheated to reflux
2. temperatureThe mixture was cooled
3. waitleft
4. filtrationthen filtered through a 25 g silica cartridge
5. washeluting with a mixture of ethyl acetate and pentane (20%)
6. customThe eluent was evaporated to dryness
7. dissolutionthe residue was redissolved in carbon tetrachloride (150 mL)
8. additionN-bromosuccinimide (6.96 g) was added
9. temperatureThe mixture was heated
10. temperatureto reflux
11. additionazo-bis-isobutyronitrile (0.1 g) was added
12. customThe resultant mixture was illuminated with a 500 W tungsten filament lamp overnight
13. temperatureAfter cooling
14. filtrationthe mixture was filtered
15. washthe solid was washed with pentane
16. customThe combined organic solutions were evaporated to dryness
17. customthe residue was purified by chromatography on silica
18. washeluting with a mixture of TBME and pentane with a gradient of 0-10%