反应详情

To a stirred solution of (R)-4-isopropyl-3-[(R)-2-methyl-2-(2-trimethylsilanyl-ethoxymethyl)-but-3-enoyl]-oxazolidin-2-one (2.93 g, 8.58 mmol) in a mixture of acetonitrile (86 mL) and water (1.72 mL) was added lithium tetrafluoroborate (1 M in acetonitrile, 42.9 mL, 42.9 mmol). The mixture was heated at reflux under nitrogen for 5 h and allowed to cool to ambient temperature. More lithium tetrafluoroborate (1 M in acetonitrile, 8.6 mL, 8.6 mmol) was added and the mixture heated at reflux for a further 75 minutes and allowed to cool to ambient temperature. The mixture was diluted with water/diethyl ether (2:3, 100 mL) and the organic layer was separated and washed with water. The combined aqueous washes were back-extracted with diethyl ether and the combined organic extracts dried over anhydrous sodium sulfate, filtered and evaporated to give the title compound (1.89 g, 91%) as a yellow oil. 1H NMR (300 MHz, CDCl3) δ 0.89 (d, J=6.9 Hz, 3H), 0.95 (d, J=6.9 Hz, 3H), 1.35 (s, 3H), 2.36-2.47 (m, 1H), 2.56-2.70 (br s, 1H), 3.47-3.54 (m, 1H), 3.91 (d, J=11.6 Hz, 1H), 4.22-4.31 (m, 2H), 4.47-4.53 (m, 1H), 4.97 (d, J=17.8 Hz, 1H), 5.17 (d, J=10.7 Hz, 1H), 6.09 (dd, J=17.8, 10.7 Hz, 1H). LCMS (m/z) 242.2 [M+H], Tr=1.82 min.

1. temperatureThe mixture was heated
2. temperatureat reflux under nitrogen for 5 h
3. temperaturethe mixture heated
4. temperatureat reflux for a further 75 minutes
5. temperatureto cool to ambient temperature
6. customthe organic layer was separated
7. washwashed with water
8. extractionThe combined aqueous washes were back-extracted with diethyl ether
9. dry with materialthe combined organic extracts dried over anhydrous sodium sulfate
10. filtrationfiltered
11. customevaporated