反应详情

To a stirred solution of diisopropylamine (13.38 mL, 94.70 mmol) in anhydrous THF (50 mL), at −70° C. and under nitrogen, was slowly added 2.5 M n-BuLi in ether (36.50 mL, 91.25 mmol). Stirred for 15 minutes, to this reaction solution was then added dropwise ethyl isobutyrate (11.51 mL, 86.09 mmol) in THF (50 mL), stirred for 20 minutes before added dropwise 4-bromo-1-butene (9.79 mL, 96.42 mmol) in HMPA (20 mL). The reaction solution was then stirred to −50° C. in 5 hours, quenched with 1M HCl (10 mL) and water (100 mL), then extracted with (3×125 mL) ether. The combined ether layer was washed with water (4×70 mL), aqueous saturated NaHCO3 (2×70 mL), dried over Na2SO4, filtered and concentrated. The crude product was flash chromatographed on 120 g silica gel 60, eluting with 1-20% EtOAc/Hexane to give the title product as clear oil (11.01 g, 75% yield). LRMS (ESI) m/z 171 [(M+H)+; calcd for C10H19O2: 171].

1. customat −70° C.
2. stirringstirred for 20 minutes
3. stirringThe reaction solution was then stirred to −50° C. in 5 hours
4. customquenched with 1M HCl (10 mL) and water (100 mL)
5. extractionextracted with (3×125 mL) ether
6. washThe combined ether layer was washed with water (4×70 mL), aqueous saturated NaHCO3 (2×70 mL)
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. customchromatographed on 120 g silica gel 60
11. washeluting with 1-20% EtOAc/Hexane