反应详情

温度

70 °C

To 1.2 g (50 mmol) of magnesium turnings in 15 mL of dry THF is added a small crystal of iodine followed by 40 μL of dibromoethane. This mixture is placed in a water bath at 50° C. and 3-isopropylbromobenzene (5.0 g, 25 mmol) in 15 mL of dry tetrahydrofuran (THF) is added dropwise over 20 min, while the bath temperature is raised to 70° C. The mixture is stirred and refluxed for 40 additional min. The solution is cooled in an ice-water bath and cyclohexanone (2.0 mL, 19 mmol) in 10 mL of dry THF is added dropwise over 15 min. The ice bath is removed and the mixture is allowed to warm to ambient temperature over 1 h. The solution is decanted into aqueous saturated NH4Cl, and combined with an ether wash of the residual magnesium turnings. The organic phase is washed twice more with aqueous NH4Cl, dried over anhydrous Na2SO4, filtered and concentrated. Chromatography on silica gel, eluting with 10% ethyl acetate in heptane, affords 2.7 g (12 mmol, 60%) of compound 1 as an oil: 1H NMR (CDCl3) δ 7.39 (m, 1H), 7.3 (m, 2H), 7.12 (m, 1H), 2.92 (m, 1H), 1.84–1.54 (m, 10H), 1.26 (d, J=7 Hz, 6H).

1. customThis mixture is placed in a water bath at 50° C.
2. temperaturerefluxed for 40 additional min
3. temperatureThe solution is cooled in an ice-water bath
4. customThe ice bath is removed
5. temperatureto warm to ambient temperature over 1 h
6. customThe solution is decanted into aqueous saturated NH4Cl
7. washwash of the residual magnesium turnings
8. washThe organic phase is washed twice more with aqueous NH4Cl
9. dry with materialdried over anhydrous Na2SO4
10. filtrationfiltered
11. concentrationconcentrated
12. washChromatography on silica gel, eluting with 10% ethyl acetate in heptane