反应详情

温度

-78 °C

N-butyllithium (1.6N hexane solution, 2.16 ml) was added dropwise to a olution of diisopropylamine (0.529 ml) in tetrahydrofuran (5 ml) at −20° C. under nitrogen atmosphere. After stirring for 20 minutes, the mixture was cooled to −78° C., and methyl isobutyrate (0.397 ml) in tetrahydrofuran (5 ml) was added dropwise over 30 minutes. The reaction mixture was further stirred for 20 minutes, 2-(3-iodopropyl)-2-phenyl-1,3-dioxolane (1.00 g) and hexamethylphosphoramide (0.602 ml) were added. After stirring at −40° C. for 3 hours, dilute hydrochloric acid was added and extracted with ethyl acetate. The ethyl acetate layer was washed with an aqueous saturated solution of sodium chloride, dried (MgSO4) and concentrated. The residue was dissolved in acetone (30 ml), 1N sulfuric acid (10 ml) was added and heated under reflux for 3 hours. The reaction mixture was cooled to room temperature, water was added to the reaction mixture and extracted with ethyl acetate. The ethyl acetate layer was washed with an aqueous saturated solution of sodium chloride, dried (MgSO4) and concentrated. The residue was subjected to silica gel chromatography to obtain methyl 2,2-dimethyl-6-oxo-6-phenylhexanoate (350 mg, yield 45%) as a colorless oil from an ethyl acetate-hexane (1:7, v/v)-eluted fraction.

1. stirringThe reaction mixture was further stirred for 20 minutes
2. stirringAfter stirring at −40° C. for 3 hours
3. extractionextracted with ethyl acetate
4. washThe ethyl acetate layer was washed with an aqueous saturated solution of sodium chloride
5. dry with materialdried (MgSO4)
6. concentrationconcentrated
7. dissolutionThe residue was dissolved in acetone (30 ml)
8. addition1N sulfuric acid (10 ml) was added
9. temperatureheated
10. temperatureunder reflux for 3 hours
11. temperatureThe reaction mixture was cooled to room temperature
12. additionwater was added to the reaction mixture
13. extractionextracted with ethyl acetate
14. washThe ethyl acetate layer was washed with an aqueous saturated solution of sodium chloride
15. dry with materialdried (MgSO4)
16. concentrationconcentrated