反应详情

温度

40 °C

To a solution of ethyl 3(R)-(tert-butyldimethylsilyloxy)-5-hexenoate (4) (80.60 g, 295.8 mmol) in MeOH (500 mL) is added a 40% KOH solution (150 mL). The mixture is stirred for 2 hours at 40° C. After the mixture is cooled to ambient temperature and MeOH is removed under reduced pressure (20 mbar) at 42° C., the obtained brown solid is dissolved in H2O (700 mL). The solution is washed with t-BuMeO (1×340 mL+3×215 mL) and then acidified with 4N HCl (222 mL) to pH=2. The yellow oil that separated from the water is extracted into t-BuMeO (6×110 mL). The combined organic layers are washed with water and dried (MgSO4). Ether is removed completely under reduced pressure (15 mbar) at 40° C. to give an orange-red oily residue (68.2 g, 94.3%). This residue is filtered two times through a thin pad of silica using t-BuMeO as solvent to afford (R)-3-(tert-butyldimethylsilyloxy)-5-hexenoic acid (5) (67.1 g, 93%) as yellow oil (GC purity 97.3%). 1H NMR (300 MHz, CDCl3): δ 11.03 (br s, 1H), 5.80 (ddt, J=17.8, 9.5 and 7.2 Hz, 1H), 5.13−5.11 (m, 1H), 5.08−5.06 (m, 1H), 4.20 (quint., J=6.5 Hz, 1H), 2.54 (dd, J=15.1 and 5.1 Hz, 1H), 2.46 (dd, J=15.1 and 7.1 Hz, 1H), 2.33−2.28 (m, 2H), 0.88 (s, 9H), 0.09 (s, 3H), 0.07 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 178.1, 133.8, 118.1, 68.8, 42.0, 41.8, 25.7, 17.9, −4.5, −5.0.

1. temperatureAfter the mixture is cooled to ambient temperature
2. customMeOH is removed under reduced pressure (20 mbar) at 42° C.
3. dissolutionthe obtained brown solid is dissolved in H2O (700 mL)
4. washThe solution is washed with t-BuMeO (1×340 mL+3×215 mL)
5. customThe yellow oil that separated from the water
6. extractionis extracted into t-BuMeO (6×110 mL)
7. washThe combined organic layers are washed with water
8. dry with materialdried (MgSO4)
9. customEther is removed completely under reduced pressure (15 mbar) at 40° C.