反应详情

A suspension of 13.9 g of pentyltriphenylphosphonium bromide in 150 ml of tetrahydrofuran is cooled to -20° under argon, 21.2 ml of 1.6M butyllithium solution in hexane are added within a period of 5 minutes and the whole is stirred for a further 30 minutes at 0°-10°. 6 g of 4-nonylbenzaldehyde in 40 ml of tetrahydrofuran are added dropwise over a period of 30 minutes to the mixture, which has been cooled to from -60° to -70°. The reaction mixture is allowed to warm spontaneously to 0°-10°, stirred at this temperature for a further 45 minutes and concentrated by evaporation. The residue is taken up in hexane/ethyl acetate (1:) and filtered over silica gel. The filtrate is concentrated by evaporation and chromatographed on silica gel with hexane. The title compound (mixture of cis- and trans-isomers) is obtained in the form of a colourless oil, which is used directly in the next stage.

1. temperatureis cooled to -20° under argon
2. temperaturehas been cooled to from -60° to -70°
3. temperatureto warm spontaneously to 0°-10°
4. stirringstirred at this temperature for a further 45 minutes
5. concentrationconcentrated by evaporation
6. filtrationfiltered over silica gel
7. concentrationThe filtrate is concentrated by evaporation
8. customchromatographed on silica gel with hexane