Reaktion #504585

Reaktionsgleichung

NBS

2-bromo-5-iodo-benzoic acid methyl ester

tributyl(ethoxyvinyl)stannane

Water

→

2-bromo-5-(2-bromo-acetyl)-benzoic acid methyl ester

Ausbeute 81.6%

Lösungsmittel

dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled to 0° C
2. 2
   Sonstigethe solvent was removed under reduced pressure
3. 3
   workup.ADDITIONThe mixture was diluted with EtOAc
4. 4
   Waschenwas washed with water and brine
5. 5
   Trocknendried with sodium sulfate
6. 6
   EinengenConcentration and purification by flash column chromatography (hexane/EtOAc=2/1)

Vorschrift

To the solution of 2-bromo-5-iodo-benzoic acid methyl ester (4.33 g, 12.7 mmol) and tributyl(ethoxyvinyl)stannane (4.79 g, 13.3 mmol) in dioxane (56 ml) was added PdCl2(PPh3)2 (322 mg). The mixture was heated at 80° C. for 17 hours and was cooled to 0° C. Water (19 ml) was added, followed by slow addition of NBS (2.33 g, 12.9 mmol) over 10 minutes period. The mixture was stirred at 0° C. for additional 40 minutes, and the solvent was removed under reduced pressure. The mixture was diluted with EtOAc, and was washed with water and brine and dried with sodium sulfate. Concentration and purification by flash column chromatography (hexane/EtOAc=2/1) gave 2-bromo-5-(2-bromo-acetyl)-benzoic acid methyl ester (3.48 g).

Quelle