(4-Cyanobenzyl)triphenylphosphonium chloride → 4-[2-(p-Cyanophenyl)vinyl]cyclohexanone

63.3 g of p-cyanobenzyl-triphenylphosphonium chloride, 17.2 g of potassium t-butylate and 195 ml of ethylene glycol dimethyl ether were placed while stirring and gassing with nitrogen in a sulphonation flask, whereby the internal temperature rose to 44° C. The brown suspension was cooled to 0° C. and treated within 2 minutes with a solution of 16.7 g of 4-formylcyclohexanone in 100 ml of ethylene glycol dimethyl ether. The cooling bath was then removed and the mixture was stirred at room temperature for a further 3.5 hours. The suspension was subsequently poured into 500 ml of water and extracted three times with 600 ml of methylene chloride each time. The organic phases were washed twice with 500 ml of 10% (wt./vol.) sodium chloride solution each time, dried over sodium sulphate, filtered and concentrated, there being obtained 76.9 g of a brownish paste. Chromatographic separation of this crude product on silica gel with methylene chloride as the eluent gave 33.0 g of 4-[2-(p-cyanophenyl)vinyl]cyclohexanone as a yellow-brownish oil.