To a solution of 1-(R)-(4-isobutylphenyl)butanol (1.13 g), methyl 4-hydroxybenzoate (917 mg) and triphenylphosphine (1.58 g) in toluene (40 ml) and tetrahydrofuran (10 ml) was added diethyl azodicarboxylate (0.95 ml) at -20° C. The mixture was stirred at -15°--20° C. for 1.5 hours and then added water (0.5 ml). The mixture was evaporated, dissolved in a mixture of n-hexane and ethyl acetate (4:1), filtered off and evaporated. The residue was chromatographed on silica gel eluting with a mixture of n-hexane and dichloromethane (1:1) to give methyl 4-[1-(S)-(4-isobutylphenyl)butoxy]benzoate as an oil (1.48 g).
