반응 #2507832

반응 방정식

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

용매

water

THF

THF

반응 조건

후처리

1. 1
   workup.WAITthe batch is left
2. 2
   추출extracted three times with MTB ether
3. 3
   세척phases are washed with sat. sodium chloride soln
4. 4
   건조and dried over sodium sulfate
5. 5
   기타The solvent is removed in vacuo
6. 6
   기타the residue is chromatographed on silica gel with heptane/toluene (1:1)
7. 7
   기타recrystallised from heptane at −20° C.

실험 절차

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.

출처