Reaktion #58849

Reaktionsgleichung

3-(3-bromophenyl)propionaldehyde

n-BuLi

→

1-bromo-3-but-3-enylbenzene

Ausbeute 50.0%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled to −78° C.
2. 2
   workup.STIRRINGstirred at −78° C. for 1 h
3. 3
   Temperaturto warm to room temperature
4. 4
   Sonstigequenched with aqueous NH4Cl
5. 5
   Einengenconcentrated under reduced pressure
6. 6
   Waschenwashed sequentially with water and brine
7. 7
   Trocknendried over Na2SO4
8. 8
   Einengenconcentrated under reduced pressure
9. 9
   EinengenChromatography of this concentrate on silica gel with a gradient of 0.5% EtOAc-hexanes to 2.0% EtOAc-hexanes

Vorschrift

A solution of 1.34 gm (3.77 mmol) of methyltriphenylphosphonium bromide in THF at 0° C. was treated dropwise with 2.3 mL of 1.6 M n-BuLi in hexanes (3.77 mmol), stirred at 0° C. for 0.25 h, cooled to −78° C., treated dropwise with a solution of 3-(3-bromophenyl)propionaldehyde (0.7 gm, 3.28 mmol) in THF, stirred at −78° C. for 1 h, allowed to warm to room temperature, quenched with aqueous NH4Cl and concentrated under reduced pressure. The resultant residue was taken up in EtOAc, washed sequentially with water and brine, dried over Na2SO4 and concentrated under reduced pressure. Chromatography of this concentrate on silica gel with a gradient of 0.5% EtOAc-hexanes to 2.0% EtOAc-hexanes gave 1-bromo-3-but-3-enylbenzene as an oil, 0.35 gm (50% yield); 1H NMR (400 MHz, CDCl3) δ: 2.33 (m, 2H), 2.66 (t, 2H, J=7.4 Hz), 4.98 (m, 2H), 5.79 (m, 1H), 7.12 (m, 2H), 7.30 (m, 2H).

Quelle