4-Cyanobenzaldehyde → 4-(2-Methoxyethenyl)benzonitrile

A suspension of 37.2 g of methoxymethyl-triphenylphosphonium chloride in 250 ml of t-butyl methyl ether is treated at room temperature while gassing with argon with 13.4 g of potassium t-butylate and stirred for 1 hour. Subsequently, the reaction mixture is treated at about 20° C. with a mixture of 9.49 g of 4-cyanobenzaldehyde and 100 mol of t-butyl methyl ether and stirred for a further 1 hours. Thereafter, the reaction mixture is partitioned in diethyl ether/water. The aqueous phase is extracted several times with diethyl ether. The organic phases are washed with water, dried over magnesium sulfate, filtered and evaporated. Chromatographic purification of the resulting crude product on silica gel with petroleum ether and toluene/hexane (vol. 3:1) gives 4-(2-methoxyvinyl)benzonitrile.