反应详情

A solution of Methyl 1,4-dioxaspiro[4.5]dec-8-ylideneacetate (4 g, 18.8 mmol) in dry THF (20 mL) was treated by nitromethane (1.5 mL, 28.3 mmol) followed by tertbutylammonium fluoride (18.8 mLot a 1M solution in THF, 0.0188 mol). The resulting mixture was stirred at reflux for 18 h under nitrogen. After cooling to RT, the mixture was diluted with water and extracted with MTBE (3×100 mL). Combined organic layers were washed with 10% sodium bicarbonate solution (20 mL), water (100 mL) and brine (50 mL), dried over sodium sulphate filtered and concentrated. Purification by flash chromatography on silica (Pet.Ether:EtOAc) afforded the title compound as a colorless liquid (2.5 g, 49%). 1H NMR (400 MHz, DMSO) δ 4.7 (s, 2H), 3.94 (s, 4H), 3.69 (s, 3H), 2.57 (s, 2H), 1.74 (m, 8H).

1. temperatureat reflux for 18 h under nitrogen
2. extractionextracted with MTBE (3×100 mL)
3. washCombined organic layers were washed with 10% sodium bicarbonate solution (20 mL), water (100 mL) and brine (50 mL)
4. dry with materialdried over sodium sulphate
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by flash chromatography on silica (Pet.Ether:EtOAc)