Réaction #2157

Équation de réaction

trimethyl borate

n-Butyl lithium

2-bromoanisole

hydrochloric acid

→

title compound

Rendement 100.4%

(2-Methoxyphenyl)boronic acid

Rendement 100.4%

Solvants

—

hexanes

tetrahydrofuran

Conditions de réaction

Traitement

1. 1
   Températurecooled to below -70° C.
2. 2
   Températuremaintaining the temperature
3. 3
   workup.ADDITIONduring the addition below -60° C
4. 4
   TempératureThe reaction mixture was cooled to 0° C.
5. 5
   Autrethe resulting layers separated
6. 6
   Extractionthe aqueous phase extracted with ethyl acetate (2×25 ml)
7. 7
   LavageThe combined orgnic layers were washed with brine (25 ml)
8. 8
   Séchagedried (MgSO4)
9. 9
   Concentrationconcentrated in vacuo

Mode opératoire

n-Butyl lithium (13.0 ml of a 1.6M solution in hexanes, 19.8 mmol) was added dropwise to a solution of 2-bromoanisole (3.74 g, 19.0 mmol) in anhydrous tetrahydrofuran (15 ml) cooled to below -70° C., maintaining the temperature during the addition below -60° C. The solution was stirred for 20 minutes before the addition of trimethyl borate (5.9 ml, 57.0 mmol), and then stirred at below -70° C. for a further hour before warming to room temperature overnight. The reaction mixture was cooled to 0° C. acidified to pH 5.0 with 5% aqueous hydrochloric acid solution (25 ml), the resulting layers separated and the aqueous phase extracted with ethyl acetate (2×25 ml). The combined orgnic layers were washed with brine (25 ml), dried (MgSO4) and concentrated in vacuo to yield the title compound as a white solid (2.9 g, 97%) which was used without further purification.

Source