反应详情

温度

5 °C

A solution of freshly distilled diisopropylamine (193.2 mL) in dry tetrahydrofurane (1 L) under argon was cooled to -5° C. with an acetone-dry ice bath. Anhydrous conditions were maintained throughout the reaction. A 1.6M solution of n-butyl lithium in hexane (862 mL) was added at such a rate that the reaction temperature did not exceed -5° C. After the addition was complete, the solution was stirred at 5° C. for 15 minutes. Then it was cooled to -78° C. and acetaldehyde N-tert- butylimine (88.5 mL) was added dropwise over 10 minutes. After stirring at -78° C. for 30 minutes. diethyl chlorophosphonate (101.2 mL) was added slowly while maintaining the reaction temperature below -65° C. and the yellow solution was stirred at -78° C. for 1 hour. The cooling bath was then removed and the mixture was allowed to warm to -10° C. over 45 minutes. Benzophenone (109.3 g) was added via a Gooch tube, and the mixture was then stirred at ambient temperature overnight. After the solvents were removed in vacuo. The residue was taken up in a solution of oxalic acid dihydrate (175 g) in water (1.5 L) and toluene (1.5 L) was added. The mixture was stirred vigorously under argon overnight. The layers were separated and the organic phase was washed in turn with 5% oxalic acid, brine, saturated sodium bicarbonate and brine. The aqueous layers were backwashed with toluene (500 mL), and the combined organic extracts were dried (MgSO4), charcoaled and concentrated to ~ 250 mL. The concentrate was passed through a short column of silica gel (500 g) made up in dichloromethane, and the product was eluted with the same solvent (7×400 mL fractions). The appropriate fractions were combined and evaporated and the residue was dissolved in warm hexane (1.2 L). The gently stirred solution was cooled slowly to 5° C. and the resulting crystalline solid was recovered by filtration to yield 109.3 g of 3,3-diphenyl-2-propenal, mp 45°-46.5° C. Concentration of the mother liquors furnished a second crop of impure 3,3-diphenyl-2-propenal which after two recrystallizations from hexane gave an additional 10.1 g of product. mp 44.5°-46° C.

1. temperatureAnhydrous conditions were maintained throughout the reaction
2. customdid not exceed -5° C
3. additionAfter the addition
4. temperatureThen it was cooled to -78° C.
5. stirringAfter stirring at -78° C. for 30 minutes
6. temperaturewhile maintaining the reaction temperature below -65° C.
7. stirringthe yellow solution was stirred at -78° C. for 1 hour
8. customThe cooling bath was then removed
9. temperatureto warm to -10° C. over 45 minutes
10. additionBenzophenone (109.3 g) was added via a Gooch tube
11. stirringthe mixture was then stirred at ambient temperature overnight
12. customAfter the solvents were removed in vacuo
13. additionwas added
14. stirringThe mixture was stirred vigorously under argon overnight
15. customThe layers were separated
16. washthe organic phase was washed in turn with 5% oxalic acid, brine, saturated sodium bicarbonate and brine
17. dry with materialthe combined organic extracts were dried (MgSO4)
18. concentrationconcentrated to ~ 250 mL
19. washthe product was eluted with the same solvent (7×400 mL fractions)
20. customevaporated
21. dissolutionthe residue was dissolved in warm hexane (1.2 L)
22. temperatureThe gently stirred solution was cooled slowly to 5° C.
23. filtrationthe resulting crystalline solid was recovered by filtration