反应详情

To magnesium turnings (9.84 g, 405 mmol) in dry THF (42 mL) as a solvent were added a few crystals of iodine and a few drops of CH2Br2. A solution of 1-chloro-4-methoxybutane (46.8 g, 382 mmol) in dry THF (90 mL) was added dropwise at a rate sufficient to maintain gentle reflux. The reaction mixture was then refluxed for 1 hour and then cooled to room temperature. The resulting Grignard reagent was then added dropwise to a suspension of CeCl3 (94.2 g, 382 mmol) in dry THF (750 mL) at 0° C. After stirring at room temperature for 2 hours, a solution of 2-bromo-3-ethoxy-cyclohex-2-enone (1) (60 g, 274 mmol) in dry THF (300 mL) was added dropwise at 0° C. The reaction mixture was stirred an additional 2 hours at room temperature and then quenched by adding a saturated NH4Cl solution (1000 mL). The mixture was further acidified to approximately pH 1 by the addition. of a 5% HCl solution and stirring was continued for an additional 2 hours. The organic layer was separated, the aqueous layer extracted with Et2O and the combined organic layers were dried over anhydrous MgSO4. The solvent was removed in vacuo and the residue purified over silica (using a isooctane/EtOAc 7:3 mixture as an eluent) to afford 65.5 g (92% yield) of the desired product as a light-yellow oil which was characterized as follows:

1. temperatureto maintain gentle reflux
2. temperatureThe reaction mixture was then refluxed for 1 hour
3. stirringThe reaction mixture was stirred an additional 2 hours at room temperature
4. customquenched
5. additionby adding a saturated NH4Cl solution (1000 mL)
6. additionThe mixture was further acidified to approximately pH 1 by the addition
7. stirringof a 5% HCl solution and stirring
8. waitwas continued for an additional 2 hours
9. customThe organic layer was separated
10. extractionthe aqueous layer extracted with Et2O
11. dry with materialthe combined organic layers were dried over anhydrous MgSO4
12. customThe solvent was removed in vacuo
13. customthe residue purified over silica (