反应详情

温度

-70 °C

Anhydrous tetrahydrofuran (22 cc) and bromomethyltriphenylphosphonium bromide (1.7 g, 3.9 mmol) are introduced into a 50-cc round-bottomed flask. This is cooled to -70° C. and potassium tert-butylate (0.44 g) is then added over 10 minutes. The mixture is stirred for 1 hour 30 minutes and 7,7-ethylenedioxy-3-methyl-2,4-octadienal (0.5 g) is then added in solution in tetrahydrofuran (3 cc) over 10 minutes. The temperature is allowed to rise to 10° C. and stirring is then performed for 2 hours 20 minutes. Water (12 cc) is quickly added and stirring is then performed for 15 minutes. After extraction, the organic phases are dried over magnesium sulphate. After evaporation of the solvents, the product obtained is placed in a mortar and is taken up with petroleum ether; the triphenylphosphine oxide which precipitates is ground until white and is then separated by filtration. After evaporation of the petroleum ether, 8,8-ethylenedioxy-1-bromo-4-methyl-1,3,5-nonatriene (0.49 g) is obtained, its characteristics being as follows:

1. customto rise to 10° C.
2. stirringstirring
3. waitis then performed for 2 hours 20 minutes
4. stirringstirring
5. waitis then performed for 15 minutes
6. extractionAfter extraction
7. dry with materialthe organic phases are dried over magnesium sulphate
8. customAfter evaporation of the solvents
9. customthe product obtained
10. customthe triphenylphosphine oxide which precipitates
11. customis then separated by filtration
12. customAfter evaporation of the petroleum ether