反应详情

A stream of nitrogen gas is passed through a mixture of 19.6 mL (41.2 mmol) of 2.1M vinyllithium in tetra-hydrofuran and 21 mL toluene to evaporate tetrahydrofuran. The resulting pale yellow suspension is diluted with 21 mL ether and cooled to -78°. To this solution is added 1.87 g (20.9 mmol) cuprous cyanide and the reaction mixture is then warmed to 0° for 2 minutes. The resulting gray suspension is cooled to -78° and 0.9 mL (10.4 mmol) of 5,6-dihydro-2H-pyran-2-one is added. The reaction mixture is stirred at -78° for 30 minutes and at -20° for 15 minutes. The reaction is quenched by the addition of saturated aqueous ammonium chloride and stirred for 1 hour at room temperature. The insoluble salts are filtered off and washed with water (1×20 mL) and ether (2×20 mL). The layers are separated and the aqueous phase is extracted with ether (2×30 mL). Combined organic extracts are dried (MgSO4), filtered and evaporated to give yellow oil which is purified by flash chromatography to obtain 4-ethenyltetrahydro-2H-pyran-2-one as a pale yellow oil.

1. customto evaporate tetrahydrofuran
2. additionThe resulting pale yellow suspension is diluted with 21 mL ether
3. temperaturecooled to -78°
4. temperaturethe reaction mixture is then warmed to 0° for 2 minutes
5. temperatureThe resulting gray suspension is cooled to -78°
6. customThe reaction is quenched by the addition of saturated aqueous ammonium chloride
7. stirringstirred for 1 hour at room temperature
8. filtrationThe insoluble salts are filtered off
9. washwashed with water (1×20 mL) and ether (2×20 mL)
10. customThe layers are separated
11. extractionthe aqueous phase is extracted with ether (2×30 mL)
12. dry with materialCombined organic extracts are dried (MgSO4)
13. filtrationfiltered
14. customevaporated
15. customto give yellow oil which
16. customis purified by flash chromatography