反应详情

The title compound of Example 1A (0.5 g, 2 mmol) dissolved in THF (20 mL) was cooled to 0° under nitrogen. Potassium tert-butoxide (0.25 g, 2.2 mmol) was added all at once. After a further 20 min, tert-butyl bromoacetate (0.39 g, 2.2 mmol) was added dropwise from a syringe. The reaction mixture was stirred 16 h at room temperature. The excess base was destroyed by the addition of wet THF (2 ml) followed by the addition of H2O (40 mL) and EtOAc (40 mL). The organic phase was dried (MgSO4) and concentrated under reduced pressure. The crude oil was purified by column chromatography (SiO2) to give the title compound (0.619 g, 85% yield) as a colorless oil: 1H NMR (400 MHz, CDCl3) δ5.64 (broad s, 1H), 5.59 (broad s, 1H,), 3.75 (s, 6H), 3.35 (s, 2H), 3.07 (s, 2H), 1.43 (s, 9H); 13CNMR (100 MHz, CDCl3) δ169.42, 168.43, 127.16, 122.35, 81.29, 54.64, 52.91, 43.53, 37.25, 27.92.

1. temperaturewas cooled to 0° under nitrogen
2. customThe excess base was destroyed by the addition of wet THF (2 ml)
3. additionfollowed by the addition of H2O (40 mL) and EtOAc (40 mL)
4. dry with materialThe organic phase was dried (MgSO4)
5. concentrationconcentrated under reduced pressure
6. customThe crude oil was purified by column chromatography (SiO2)