p-Bromoacetophenone → (E)-ethyl 3-(4-bromophenyl)-but-2-enoate
Reaktionsgleichung
CC(C)([O-:4])C.[K+].[Br:7][C:8]1[CH:13]=[CH:12][C:11]([C:14](=O)[CH3:15])=[CH:10][CH:9]=1.[CH2:17]1[CH2:21][O:20][CH2:19][CH2:18]1>>[CH2:19]([O:20][C:21](=[O:4])/[CH:17]=[C:14](/[C:11]1[CH:12]=[CH:13][C:8]([Br:7])=[CH:9][CH:10]=1)\[CH3:15])[CH3:18]Komponenten
4
Versuchsvorschrift
A solution of potassium tert-butoxide (10.45 g, 90.43 mmol) in THF (250 ml) was stirred under nitrogen atmosphere. A solution of triethyl phosphonoacetate (18.1 ml, 90.43 mmol) in THF (100 ml) was then added and the reaction mixture was stirred for 30 minutes at room temperature. A solution of 1-(4-Bromo-phenyl)-ethanone (6 g, 30.14 mmol) in THF (100 ml) was then added dropwise over 5 minutes. The reaction mixture was heated to reflux. After 3 hours the reaction mixture was cooled to ambient temperature and THF was removed under reduced pressure. The reaction mixture was dissolved in H2O, extracted with EtOAc, washed with H2O and brine, dried (Na2SO4) and concentrated under reduced pressure. The crude product was purified by column chromatography on silica (Hept:EtOAc 8:2) to afford the title compound (8.1 g, 99%).