Reaktion #324714

Reaktionsgleichung

2,5-dibromo-1,3-dimethylbenzene

isopropylmagnesium chloride

n-butyllithium

3-bromopropene

CuCN

LiCl

→

title compound

5-Allyl-2-bromo-1,3-dimethylbenzene

Lösungsmittel

tetrahydrofurane

tetrahydrofurane

tetrahydrofurane

n-hexane

tetrahydrofurane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe mixture is stirred for 2 hours
2. 2
   workup.ADDITIONis added dropwise
3. 3
   workup.STIRRINGthe mixture is stirred for 1 hour
4. 4
   Temperaturwarmed to room temperature
5. 5
   workup.STIRRINGstirred for further 12 hours
6. 6
   SonstigeThen the reaction is quenched by addition of saturated aqueous NH4Cl solution
7. 7
   ExtraktionThe mixture is extracted with diethylether
8. 8
   Trocknenthe organic phase is dried (MgSO4)
9. 9
   Einengenconcentrated
10. 10
    SonstigeThe residue is chromatographed on silica gel (dichloromethane)

Vorschrift

To a solution of isopropylmagnesium chloride (6.15 mL of a 2 M solution in tetrahydrofurane) in tetrahydrofurane (75 mL) is added dropwise at 0° C. n-butyllithium (15.4 mL of a 1.6 M solution in n-hexane). The mixture is stirred for 10 minutes, a solution of 2,5-dibromo-1,3-dimethylbenzene (5 g) in tetrahydrofurane (75 mL) is added within 10 minutes. The mixture is stirred for 2 hours, cooled to −40° C. and then CuCN×LiCl (5.5 mL of a 1 M solution in tetrahydrofurane) is added dropwise. After stirring for 5 minutes 3-bromopropene (6.6 mL) is added dropwise, the mixture is stirred for 1 hour, warmed to room temperature and stirred for further 12 hours. Then the reaction is quenched by addition of saturated aqueous NH4Cl solution. The mixture is extracted with diethylether, the organic phase is dried (MgSO4) and concentrated. The residue is chromatographed on silica gel (dichloromethane) to give the title compound. Yield: 3.76 g; LC (method 8): tR=0.83 min; Mass spectrum (ESI+): m/z=225 [M+H]+.

Quelle