反应详情

温度

-40 °C

A suspension of 3,4,5-trimethoxybenzylphosphonium bromide (1.047 g, 2 mmol) in 12 mL dry tetrahydrofuran was stirred under nitrogen while cooling to −40° C. then adding 1.52 mL of 1.6M butyllithium in hexane (2.44 mmol) dropwise over six minutes below −25° C. The mixture was kept at −15° C. for ten minutes before cooling to −70°. 7 (0.748 g, 2.04 mmol) was added as a solution in 3 mL THF dropwise below −60° C. and the pale orange solution allowed to reach 20° C. over a period of one hour. After stirring for a further three hours the mixture was allowed to stand overnight. Water (8.5 mL) was added slowly and the mixture extracted three times with 8.5 mL t-butyl methyl ether. The organics were washed with brine, dried and evaporated at 30° C. The crude was purified by flash chromatography (cyclohexane:AcOEt 95:5) after removing triphenylphosphine oxide by filtration to give a colourless oil 8 which solidified on standing (0.70 g):

1. waitThe mixture was kept at −15° C. for ten minutes
2. temperaturebefore cooling to −70°
3. stirringAfter stirring for a further three hours the mixture
4. waitto stand overnight
5. extractionthe mixture extracted three times with 8.5 mL t-butyl methyl ether
6. washThe organics were washed with brine
7. customdried
8. customevaporated at 30° C
9. customThe crude was purified by flash chromatography (cyclohexane:AcOEt 95:5)
10. customafter removing triphenylphosphine oxide
11. filtrationby filtration