Reaktion #42400

Reaktionsgleichung

methyl 3-bromo-5-(hydroxymethyl)benzoate

cesium carbonate

potassium carbonate

trimethyl boroxine

→

title compound

Methyl 3-(hydroxymethyl)-5-methylbenzoate

Lösungsmittel

dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture is refluxed for 12 h
2. 2
   Sonstigepartitioned between water and ethyl acetate
3. 3
   WaschenThe organic layer is washed with water and brine
4. 4
   Trocknendried (magnesium sulfate)
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated under reduced pressure
7. 7
   Sonstigefollowed by purification by flash column chromatography (silica, 25% ethyl acetate/hexanes)

Vorschrift

To a stirred solution of methyl 3-bromo-5-(hydroxymethyl)benzoate (4.53 g, 18.5 mmol) in dioxane (74 mL) is added cesium carbonate (6.0 g, 18.5 mmol), potassium carbonate (5.1 g, 37 mmol), and palladium(0)tetrakis(triphenylphosphine) (2.1 g, 1.85 mmol), followed by trimethyl boroxine (5.1 mL, 37 mmol). The reaction mixture is refluxed for 12 h, cooled to room temperature, and then partitioned between water and ethyl acetate. The organic layer is washed with water and brine, dried (magnesium sulfate), filtered, and concentrated under reduced pressure. The black oil is adsorbed onto silica gel followed by purification by flash column chromatography (silica, 25% ethyl acetate/hexanes) to provide the title compound. 1H NMR (300 MHz, CDCl3) δ 7.75 (s, 1H), 7.65 (s, 1H), 7.39 (s, 1H), 5.31 (br s, 1H), 4.53 (s, 1H), 3.84 (s, 3H), 2.36 (s, 3H).

Quelle