反应详情

Under a nitrogen atmosphere, 24.85 9 (0.0885 mol) of tert-butyl-dimethyl-(2-ethyl-5-methoxy-benzyloxy)-silane (16) and 15.77 g (0.0885 mmol) of NBS were combined in 500 mL of carbon tetrachloride, followed by the addition of 100 g of silica gel 60 (EM Science). The reaction was allowed to stir for 16 hours in the absence of light. The reaction mixture was filtered and the silica gel was washed with dichloromethane. The filtrate was washed with dichloromethane (1×300 mL). The combined organic extracts were washed with 1M NaOH (2×300 mL), dilute NaHSO3 (1×200 mL) and brine (1×200 mL), dried over magnesium sulfate, filtered and concentrated in vacuo to yield crude tert-butyl-dimethyl-(4-bromo-2-ethyl-5-methoxy-benzyloxy)-silane (17). Crude tert-butyl-dimethyl-(4-bromo-2-ethyl-5-methoxy-benzyloxy)-silane (17) was chromatographed on a silica gel column with 20% CHCl3 in hexane to afford 19.70 g (62%) of tert-butyl-dimethyl-(4-bromo-2-ethyl-5-methoxy-benzyloxy)-silane (17).

1. additionfollowed by the addition of 100 g of silica gel 60 (EM Science)
2. filtrationThe reaction mixture was filtered
3. washthe silica gel was washed with dichloromethane
4. washThe filtrate was washed with dichloromethane (1×300 mL)
5. washThe combined organic extracts were washed with 1M NaOH (2×300 mL), dilute NaHSO3 (1×200 mL) and brine (1×200 mL)
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto yield crude tert-butyl-dimethyl-(4-bromo-2-ethyl-5-methoxy-benzyloxy)-silane (17)
10. customCrude tert-butyl-dimethyl-(4-bromo-2-ethyl-5-methoxy-benzyloxy)-silane (17) was chromatographed on a silica gel column with 20% CHCl3 in hexane