反应 #2507832

反应方程式

hydrochloric acid

potassium tert-butoxide

(6-fluoro-3-pentylchroman-7-ylmethyl)triphenylphosphonium bromide

6,8-difluoro-2H-chromene-3-carbaldehyde

→

6,8-difluoro-3-[2-(6-fluoro-3-pentylchroman-7-yl)vinyl]-2H-chromene

溶剂

water

THF

THF

反应条件

后处理

1. 1
   workup.WAITthe batch is left
2. 2
   萃取extracted three times with MTB ether
3. 3
   洗涤phases are washed with sat. sodium chloride soln
4. 4
   干燥and dried over sodium sulfate
5. 5
   其他The solvent is removed in vacuo
6. 6
   其他the residue is chromatographed on silica gel with heptane/toluene (1:1)
7. 7
   其他recrystallised from heptane at −20° C.

实验过程

10.2 g (17.7 mmol) of (6-fluoro-3-pentylchroman-7-ylmethyl)triphenylphosphonium bromide are dissolved in 50 ml of THF, and 2.0 g (17.8 mmol) of potassium tert-butoxide are added with ice cooling. After 1 h, a solution of 6,8-difluoro-2H-chromene-3-carbaldehyde in 50 ml of THF is slowly added dropwise, and the batch is left to stir overnight at room temp. The solution is subsequently added to water, acidified using dil. hydrochloric acid and extracted three times with MTB ether. The combined org. phases are washed with sat. sodium chloride soln. and dried over sodium sulfate. The solvent is removed in vacuo, and the residue is chromatographed on silica gel with heptane/toluene (1:1) and recrystallised from heptane at −20° C., giving 6,8-difluoro-3-[2-(6-fluoro-3-pentylchroman-7-yl)vinyl]-2H-chromene as yellow crystals.

来源