反应详情

To a cooled solution (0° C.) of the epoxide from Example 1, Step A above (32.7 g, 125 mmol) in benzene (200 ml) is added dropwise 7.6 ml BF3 ·OEt2 (62 mmol). The cooling bath is removed and the reaction mixture warmed to room temperature and stirred for 2 hours. The benzene is removed under reduced pressure and provides a residue which is dissolved in ether (300 ml) and washed with saturated ammonium chloride. The ether layer is concentrated under reduced pressure to provide 26 g (80%) of 2-(4-fluoro-3-methylphenyl)-4,4,6,6-tetramethylcyclohexanone. The ketone is recrystallized from pentane to give a white solid; m.p. 63°-64° C.: 1H NMR δ=1.05 (s,3), 1.1 (s,3), 1.3 (s,3), 1.32 (s,3), 1.75 (s,2), 2.0 (q,2), 2.3 (s,3), 3.95 (dd,1), 6.95 (m,3).

1. customThe cooling bath is removed
2. customThe benzene is removed under reduced pressure
3. customprovides a residue which
4. washwashed with saturated ammonium chloride
5. concentrationThe ether layer is concentrated under reduced pressure