Reaktion #515404

Reaktionsgleichung

magnesium

2-bromo-5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene

ammonium chloride

dibromoethane

methoxyallene

→

expected product

Ausbeute 47.0%

3-(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-1-propyne

Ausbeute 47.0%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONare introduced into a four litre reactor under a stream of nitrogen
2. 2
   Temperaturto maintain the
3. 3
   TemperaturThe reaction medium is then cooled to −5° C.
4. 4
   workup.STIRRINGThe mixture is stirred for one hour at −5° C.
5. 5
   Sonstigeto return to room temperature
6. 6
   workup.STIRRINGis stirred for two hours
7. 7
   Extraktionextracted with ethyl acetate
8. 8
   Sonstigethe organic phase is separated out after settling
9. 9
   Trocknendried over magnesium sulphate
10. 10
    Sonstigeevaporated
11. 11
    SonstigeThe oil obtained
12. 12
    workup.DISTILLATIONis distilled at 0.02 mm Hg
13. 13
    Sonstigepassing at 95-100° C.
14. 14
    Sonstigeis collected

Vorschrift

20 g (0.82 mol) of magnesium activated with 0.1 ml of dibromoethane are introduced into a four litre reactor under a stream of nitrogen. A solution of 200 g (0.75 mol) of 2-bromo-5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalene is added dropwise so as to maintain the reflux of the THF and the mixture is stirred at 50° C. for two hours. The reaction medium is then cooled to −5° C. and 1.2 g (8.2 mmol) of CuBr are added and a solution of 58 g (0.82 mol) of methoxyallene in 100 ml of THF is introduced dropwise. The mixture is stirred for one hour at −5° C. and is then allowed to return to room temperature and is stirred for two hours. The reaction medium is poured into saturated ammonium chloride solution and extracted with ethyl acetate, and the organic phase is separated out after settling has taken place, dried over magnesium sulphate and evaporated. The oil obtained is distilled at 0.02 mm Hg and the fraction passing at 95-100° C. is collected. 79 g (47%) of the expected product are obtained in the form of a colourless oil.

Quelle