[Br-].[CH2:2]([C:7]1[CH:12]=[CH:11][C:10]([CH2:13][P+](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=[CH:9][CH:8]=1)[CH2:3][CH2:4][CH2:5][CH3:6].[C:33]([CH:35]1[CH2:40][CH2:39][CH:38]([CH:41]=O)[CH2:37][CH2:36]1)#[N:34].O>COC(C)(C)C>[CH2:2]([C:7]1[CH:12]=[CH:11][C:10]([CH:13]=[CH:41][CH:38]2[CH2:39][CH2:40][CH:35]([C:33]#[N:34])[CH2:36][CH2:37]2)=[CH:9][CH:8]=1)[CH2:3][CH2:4][CH2:5][CH3:6]A mixture of 2.51 g of (p-pentylphenyl)methyl-triphenylphosphonium bromide and 615 mg of 4-cyanocyclohexanecarboxaldehyde (cis/trans mixture about 1:1) in 30 ml of t-butyl methyl ether was placed at 0° C. in a sulphonation flask while gassing with argon, the mixture was treated within 2 minutes with 673 mg of solid potassium t-butylate and the mixture was subsequently stirred at 0° C. for a further 1.5 hours. The red-brown, heterogeneous mixture was then poured into 100 ml of water and extracted three times with 100 ml of diethyl ether each time. The organic phases were washed twice with 50 ml of water each time and once with 50 ml of saturated sodium chloride solution, dried over magnesium sulphate and concentrated. The residue was suspended in 150 ml of hexane, freed from precipitated triphenylphosphine oxide by filtration (back-washing with hexane) and the filtrate was concentrated. Low-pressure chromatography (0.4 bar) of the resulting oil (1.36 g) on silica gel with 3% ethyl acetate/petroleum ether as the eluant gave 1.02 g (81%) of 4-[2-(p-pentylphenyl)ethenyl]cyclohexanecarbonitrile as a colourless oil; Rf values of this isomer mixture (10% ethyl acetate/petroleum ether): 0.27 and 0.36.
Loading…
