반응 #51264

반응 방정식

magnesium

methoxyallene

ammonium chloride

4,4-dimethyl-8-iodochroman

→

3-(4,4-dimethylchroman-8-yl)prop-1-yne

용매

ethyl ether

ethyl ether

반응 조건

후처리

1. 1
   workup.ADDITIONare introduced into a three-necked flask under argon
2. 2
   온도so as to maintain the
3. 3
   온도reflux of the solvent
4. 4
   온도It is subsequently cooled to −5° C.
5. 5
   workup.ADDITIONis introduced dropwise
6. 6
   workup.STIRRINGThe mixture is stirred for one hour at −5° C.
7. 7
   기타to return to room temperature
8. 8
   workup.STIRRINGstirred for two hours
9. 9
   추출extracted with ethyl acetate
10. 10
    기타the organic phase is separated
11. 11
    건조dried over magnesium sulphate
12. 12
    기타evaporated
13. 13
    기타The residue obtained
14. 14
    기타is purified by chromatography on a silica column
15. 15
    세척eluted with heptane
16. 16
    기타After evaporating the solvents, 1.30 g (65%) of the expected compound
17. 17
    기타are collected in the form of a yellow oil

실험 절차

280 mg (11.5 mmol) of magnesium, activated with 1 drop of dibromoethane, are introduced into a three-necked flask under argon. A solution of 3.00 g (10.4 mmol) of 4,4-dimethyl-8-iodochroman in 15 ml of ethyl ether is added dropwise, so as to maintain the reflux of the solvent, and the reaction mixture is stirred at 35° C. for 15 minutes. It is subsequently cooled to −5° C., 40 mg (0.2 mmol) of CuI are added and a solution composed of 1.24 g (17.7 mmol) of methoxyallene in 5 ml of ethyl ether is introduced dropwise. The mixture is stirred for one hour at −5° C., allowed to return to room temperature and stirred for two hours. The reaction mixture is poured into a saturated ammonium chloride solution and extracted with ethyl acetate and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. The residue obtained is purified by chromatography on a silica column eluted with heptane. After evaporating the solvents, 1.30 g (65%) of the expected compound are collected in the form of a yellow oil.

출처