A solution of 11.5 g of diethylazodicarboxylate in tetrahydrofuran is added to a mixture of 20.6 g of 4-cyano-4-heptylcyclohexyl p-hydroxybenzoate (obtainable by esterification of 4-cyano-4-heptylcyclohexanol with p-benzyloxybenzoic acid and cleavage of the benzyl group by catalytic hydrogenation), 11.5 g of optically active hexyl lactate and 15.7 g of triphenylphosphine in 150 ml of tetrahydrofuran, stirring is carried out for one hour at 50° and the solvent is removed after 12 hours. The residue is dissolved in 100 ml of hot toluene, cooled down, filtered and the filtrate purified as usual by chromatography and crystallization. Optically active hexyl p-(4-cyano-4-heptylcyclohexyloxycarbonyl)phenoxypropionate is obtained.
