反应详情

Under a nitrogen atmosphere, a solution of 3.76 g of 4-nitrophenol in 25 ml of N,N-dimethylformamide was added dropwise to an ice-cooled suspension of 1.08 g of 60% oily sodium hydride in 50 ml of N,N-dimethylformamide, and the mixture was stirred at room temperature for 1 hour. Then, the reaction solution was cooled to 0° C. and a solution of 10 g of 5-acetoxy-4,6-di-t-butyl-2-iodomethyl-2-methyl-2,3-dihydrobenzofuran synthesized in Example 70-2) in 25 ml of N,N-dimethylformamide was added dropwise, and the mixture was heated under reflux for 14 hours. After cooling, the reaction solution was combined with a saturated aqueous ammonium chloride solution and extracted with ethyl acetate, and the organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and then concentrated. The concentrate was purified by silica gel column chromatography eluting with n-hexane containing 20% ethyl acetate to give 6.57 g of 5-acetoxy-4,6-di-t-butyl-2-methyl-2-(4-nitrophenoxymethyl)-2,3-dihydrobenzofuran (rotamer mixture) as a pale yellow oil (yield 64%).

1. temperaturecooled
2. temperatureThen, the reaction solution was cooled to 0° C.
3. temperaturethe mixture was heated
4. temperatureunder reflux for 14 hours
5. temperatureAfter cooling
6. extractionextracted with ethyl acetate
7. washthe organic layer was washed with saturated brine
8. dry with materialdried over anhydrous magnesium sulfate
9. concentrationconcentrated
10. customThe concentrate was purified by silica gel column chromatography
11. washeluting with n-hexane containing 20% ethyl acetate