反应详情

In 175 ml. of dry tetrahydrofuran was dissolved 3.9 g. of diisopropylamine with stirring under nitrogen. The solution was cooled to -65°, and 16 ml. of 2.4 molar n-butyllithium in hexane was added dropwise. The solution was stirred at constant temperature for 40 minutes, and to it was added dropwise 10 g. of 1-dimethylamino-2-(3-trifluoromethylphenyl)-1-butene-3-one dissolved in 50 ml. of tetrahydrofuran, and 25 ml. of hexamethylphosphoramide. The temperature at the end of the addition was -70°. The mixture was stirred for 1 hour at constant temperature and then 4.7 g. of pivaloyl chloride dissolved in 25 ml. of tetrahydrofuran was added dropwise. The mixture was stirred overnight and allowed to warm to ambient temperature. To the mixture was then added saturated potassium dihydrogen phosphate solution to bring its pH to 6, and the quenched reaction mixture was then partitioned between water and diethyl ether. The organic layer was dried over magnesium sulfate and evaporated under vacuum to obtain a dark oil, which was chromatographed on 300 g. of silica gel, eluting with 20% ethyl acetate in dichloromethane. The yield was 3.6 g. of the desired intermediate product.

1. temperatureThe solution was cooled to -65°
2. additionto it was added dropwise 10 g
3. additionThe temperature at the end of the addition
4. customwas -70°
5. stirringThe mixture was stirred for 1 hour at constant temperature
6. stirringThe mixture was stirred overnight
7. customthe quenched reaction mixture
8. customwas then partitioned between water and diethyl ether
9. dry with materialThe organic layer was dried over magnesium sulfate
10. customevaporated under vacuum
11. customto obtain a dark oil, which
12. customwas chromatographed on 300 g
13. washof silica gel, eluting with 20% ethyl acetate in dichloromethane