[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 at 0° C. was placed in a sulphonation flask under argon gasification, treated within 2 minutes with 673 mg of solid potassium t-butylate and subsequently stirred at 0° C. for a further 1.5 hours. Then, the red-brown heterogeneous mixture was 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 (rinsing 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.
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