反应详情

A solution of 36.72 g of triphenylphosphine in 200 ml of methylene chloride was treated slowly at -20° C. with 23.22 g of carbon tetrabromide and stirred for a further 10 minutes. Subsequently, the mixture was added dropwise by means of a cannula to a solution, cooled to -60° C., of 6.30 g of 4-formylcyclohexanone in 100 ml of methylene chloride. The mixture was stirred at -60° C. for a further 15 minutes and then partitioned in water/methylene chloride. The aqueous phases were extracted a further twice with methylene chloride. The organic phases were washed twice with water, dried over magnesium sulphate and evaporated. Low-pressure chromatography of the resulting, pale yellow oil (16 g) on silica gel with ethyl acetate/petroleum ether (vol. 10:90) gave 12.08 g (85.8%) of 4-(2,2-dibromovinyl)cyclohexanone as a pale yellow liquid.

1. additionSubsequently, the mixture was added dropwise by means of a cannula to a solution
2. stirringThe mixture was stirred at -60° C. for a further 15 minutes
3. custompartitioned in water/methylene chloride
4. extractionThe aqueous phases were extracted a further twice with methylene chloride
5. washThe organic phases were washed twice with water
6. dry with materialdried over magnesium sulphate
7. customevaporated