反应详情

Twenty-five grams of n-hexyltriphenylphosphonium bromide were dissolved in 350 ml. of dry tetrahydrofuran and cooled to -10° C. To the solution were added 37 ml. of a 1.6M solution of n-butyllithium in hexane. The solution was slowly warmed to room temperature and stirred for one hour. The solution was then cooled to 0° C. and a solution of 2.38 g. of 2,3- dihydro-2-hydroxy-4,5-dichlorobenzofuran in 20 ml. of tetrahydrofuran was added. The reaction was allowed to reflux for approximately 18 hours. The solution was then cooled and evaporated to dryness. Ethyl acetate and water were added and the pH was adjusted to 2.5. The layers were separated. The organic layer was washed with a saturated sodium chloride solution, filtered through sodium sulfate, and evaporated to dryness. The residue was purified by high pressure liquid chromatography giving 2.51 g. of the desired intermediate as a mixture of cis and trans isomers.

1. additionTo the solution were added 37 ml
2. temperatureThe solution was then cooled to 0° C.
3. temperatureto reflux for approximately 18 hours
4. temperatureThe solution was then cooled
5. customevaporated to dryness
6. additionEthyl acetate and water were added
7. customThe layers were separated
8. washThe organic layer was washed with a saturated sodium chloride solution
9. filtrationfiltered through sodium sulfate
10. customevaporated to dryness
11. customThe residue was purified by high pressure liquid chromatography
12. customgiving 2.51 g