反应详情

DL-2-Hydroxy-3-butenoic acid methyl ester (5 g, 43.06 mmol), 3,4-dihydro-2H-pyran (19.6 mL, 215.3 mmol), p-TsOH.H2O (40 mg, 0.22 mmol) and dichloromethane (200 mL) were mixed, and stirred at room temperature for 3 hours. The solution was concentrated. The dried residue was dissolved in THF (250 mL) at 0° C. LiAlH4 (3.27 g, 86.12 mmol) was added portionwise under N2. The reaction mixture was slowly warmed up from 0° C. to room temperature, stirred overnight and cooled to 0° C. H2O (5 mL) was added dropwise via syringe. The solvent was removed under reduced pressure. The residue was extracted with THF (500 mL). The solution was filtered, and dried with silica gel powder (20 g), and purified by flash chromatography eluting with 20% ethyl acetate in hexanes (2 L) to give the title compound (6.80 g, 89%). MS (DCI) m/z 177.44 (M+H)+; 1H NMR (400 MHz, CDCl3) δ ppm 1.44–1.62 (m, 4 H) 1.71 (m, 1 H) 1.84 (m, 1 H) 3.40–3.62 (m, 3 H) 3.88 (m, 1 H) 4.16 (m, 1 H) 4.62–4.81 (m, 2 H) 5.11–5.36 (m, 2 H) 5.81 (m, 1 H).

1. concentrationThe solution was concentrated
2. dissolutionThe dried residue was dissolved in THF (250 mL) at 0° C
3. temperatureThe reaction mixture was slowly warmed up from 0° C. to room temperature
4. stirringstirred overnight
5. temperaturecooled to 0° C
6. customThe solvent was removed under reduced pressure
7. extractionThe residue was extracted with THF (500 mL)
8. filtrationThe solution was filtered
9. customdried with silica gel powder (20 g)
10. custompurified by flash chromatography
11. washeluting with 20% ethyl acetate in hexanes (2 L)