反应详情

温度

-20 °C

n-Butyllithium (1.6 mL of a 1.6 M solution in hexane, 2.6 mmol) was added dropwise to a suspension of 3,4,5-trimethoxybenzyltriphenylphosphonium bromide (1.1 g, 2.1 mmol) in THF (15 mL) at −20° C. The brick red solution was stirred at −20° C. for 30 min, cooled to −78° C., then a solution of 45 (0.88 g, 2.14 mmol) in THF (5 mL) was added dropwise. The reaction mixture was allowed to warm to rt overnight, then poured into t-BuOMe (ca. 20 mL) and water (ca. 20 mL), the layers were separated and the aqueous layer was re-extracted with t-BuOMe. The combined organic extracts were washed with brine, dried (Na2SO4) and evaporated to dryness. Purification by column chromatography (SiO2, EtOAc:cyclohexane 1:1) gave 46 (0.355 g, 29%):

1. temperaturecooled to −78° C.
2. temperatureto warm to rt overnight
3. customthe layers were separated
4. extractionthe aqueous layer was re-extracted with t-BuOMe
5. washThe combined organic extracts were washed with brine
6. dry with materialdried (Na2SO4)
7. customevaporated to dryness
8. customPurification by column chromatography (SiO2, EtOAc:cyclohexane 1:1)