Tetrahydrofuran → HCID 67872175, compound

Participants

Reaction Steps

44 g of n-butyltriphenylphosphonium bromide are suspended in 500 ml of dry tetrahydrofuran under argon and cooled to -50°. 69 ml of 1.33N n-butyllithium in hexane are added thereto. The orange coloured suspension is warmed to room temperature and then again cooled to -50°. 14 g of (5S)-5-acetyl-2-methyl-2-cyclohexen-1-one dissolved in 20 ml of dry tetrahydrofuran are added dropwise thereto over a period of 20 minutes. The cooling bath is then removed and the suspension is left to warm to room temperature. After stirring for 2 hours the reaction mixture is filtered through siliceous earth. The filtrate is evaporated, the dark residue is dissolved in 500 ml of ethyl acetate and washed twice with 200 ml of water each time. The organic phase is dried over sodium sulphate and evaporated. The thus-obtained oil is purified by column chromatography on silica gel with hexane/ethyl acetate (95:5) as the elution agent. There is obtained (5S)-2-methyl-5-[(Z)-1-methyl-1-pentenyl]-2-cyclohexen-1-one which still contains about 15% of the corresponding (E)-isomer.

Provenance & Evidence