反应详情

Triethyl phosphonoacetate (1.13 mL, 5.70 mmol) was added dropwise to a stirring suspension of sodium hydride (0.22 g of a 60% dispersion in oil, 5.43 mmol) in THF (15 mL) at 0° C. under argon. After 20 minutes, ketone 3 (0.75 g, 5.43 mmol) in THF (6 mL) was added dropwise. The mixture was allowed to warm to room temperature and stirred for 16 hours. Water (5 mL) was added, and the mixture was extracted with ether (15 mL×3). The combined organic fractions were washed with brine and dried (MgSO4). The solvent was evaporated under reduced pressure. The residue was chromatographed (SiO2, heptane/ethyl acetate, 95:5) to give the ester 4 (0.81 g, 72%) as a colorless oil; Rf(heptane/ethyl acetate, 8:2) 0.66; νmax(film)/cm−1 1715 (C═O), 1652 (C═C); δH (400 MHz; CDCl3): 5.80 (1H, quint, J=2.2, CHCO2Et), 4.15 (2H, q, J=7.1, CO2CH2Me), 2.79 (1H, dd, J=19.5, 8.1), 2.69 (1H, ddt, J=19.8, 7.3, 2.3), 2.47 (1H, dd, J=17.3, 7.2), 2.34 (1H, ddt, J=17.3, 5.6, 1.8), 2.14 (1H, m), 2.02 (1H, m), 1.60–1.22 (8H, m); m/z (ES+) 209 (M+H, 57%), 455 (2M+K, 67).

1. extractionthe mixture was extracted with ether (15 mL×3)
2. washThe combined organic fractions were washed with brine
3. dry with materialdried (MgSO4)
4. customThe solvent was evaporated under reduced pressure
5. customThe residue was chromatographed (SiO2, heptane/ethyl acetate, 95:5)