反应详情

60% NaH dispersion in mineral oil (0.96 g, 24 mmol) was added to a solution of diethyl cyanomethylphosphonate (4.25 g, 24 mmol) in THF (30 ml) while cooling with ice water. The mixture was stirred for 30 min and a solution of 3,3,5,5-tetramethylcyclohexanone (3.08 g, 20 mmol) in THF (10 ml) was added dropwise. Cooling bath was removed and the mixture was stirred at room temperature for 72 h. It was poured into ice water (100 ml) and extracted with diethyl ether (350 ml). The combined organic phases were washed with brine, dried over MgSO4, filtered and evaporated. The crude product was purified by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 10:1) to give 20 (2.38 g, 71%) as a colorless oil. 1H-NMR (CDCl3, TMS):0.97 and 1.01 (total 12H, both s, 3′,5′-CH3); 1.36 (2H, s, 4′-CH2); 2.01 (2H, s, 2′-CH2); 2.26 (2H, s, 6′-CH2) and 5.14 ppm (1H, s, ═CH).

1. temperatureCooling bath
2. customwas removed
3. stirringthe mixture was stirred at room temperature for 72 h
4. additionIt was poured into ice water (100 ml)
5. extractionextracted with diethyl ether (350 ml)
6. washThe combined organic phases were washed with brine
7. dry with materialdried over MgSO4
8. filtrationfiltered
9. customevaporated
10. customThe crude product was purified by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 10:1)