Reaktion #159444

Reaktionsgleichung

5-bromo-2-ethylphenyllead triacetate

bicyclo[3.2.1]octane-2,4-dione

toluene

→

3-(5-bromo-2-ethylphenyl)bicyclo[3.2.1]octane-2,4-dione

Ausbeute 55.1%

Lösungsmittel

chloroform

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe mixture is stirred at 80° C. for 1 hour
2. 2
   Temperatur(pre-heated oil bath)
3. 3
   Temperaturto cool to room temperature
4. 4
   Sonstigequenched with 1M hydrochloric acid
5. 5
   Sonstigethe organic phase separated
6. 6
   WaschenThe aqueous phase is further washed with dichloromethane (×2)
7. 7
   Sonstigeagain the phases are separated
8. 8
   SonstigeAll organics are combined then evaporated under reduced pressure
9. 9
   Sonstigeto give a crude oil, which
10. 10
    Sonstigeis purified by flash column chromatography on silica gel (30% to 50% ethyl acetate/iso-hexane eluant ratio
11. 11
    SonstigeThe resulting gum is then recrystalised from dichloromethane/hexane

Vorschrift

To a solution of 5-bromo-2-ethylphenyllead triacetate (16.34 g, 28.80 mmol) in chloroform (160 ml) is added bicyclo[3.2.1]octane-2,4-dione (3.61 g, 26.10 mmol) and 4-dimethylaminopyridine (16.63 g, 131 mmol), and the reaction mixture is stirred at room temperature for 5 minutes. Next toluene (40 ml) is added, and the mixture is stirred at 80° C. for 1 hour (pre-heated oil bath). The reaction mixture is allowed to cool to room temperature, quenched with 1M hydrochloric acid, and the organic phase separated. The aqueous phase is further washed with dichloromethane (×2), and again the phases are separated. All organics are combined then evaporated under reduced pressure to give a crude oil, which is purified by flash column chromatography on silica gel (30% to 50% ethyl acetate/iso-hexane eluant ratio, then 10% methanol/dichloromethane eluant ratio). The resulting gum is then recrystalised from dichloromethane/hexane to afford 3-(5-bromo-2-ethylphenyl)bicyclo[3.2.1]octane-2,4-dione (4.62 g, 55%) as a cream coloured solid.

Quelle