反应详情

温度

0 °C

A solution, cooled to 0° C., of 90.9 g of tetrabromomethane in 100 ml of methylene chloride was treated under argon gasification within 20 minutes with a solution of 143.9 g of triphenylphosphine in 200 ml of methylene chloride. The clear orange solution was stirred at 0° C. for a further 5 minutes and then treated dropwise within 10 minutes at 0° C. with a solution of 25 g of trans-4-pentylcyclohexanecarboxaldehyde (purity about 82%) in 80 ml of methylene chloride. After stirring at 0° C. for 30 minutes, the mixture was poured into 2.5 l of hexane and the precipitate which separated was filtered off. The filtrate was concentrated, digested with 1 l of hexane, filtered and again concentrated. Low-pressure chromatography (0.5 bar) of the residue (52.7 g) on silica gel with hexane gave 35.9 g (77.4%) of trans-1-(2,2-dibromovinyl)-4-pentylcyclohexane as a colourless oil; Rf-value (hexane) 0.58.

1. stirringAfter stirring at 0° C. for 30 minutes
2. customthe precipitate which separated
3. filtrationwas filtered off
4. concentrationThe filtrate was concentrated
5. filtrationfiltered
6. concentrationagain concentrated