Reacción #62240

Ecuación de reacción

hydrogen peroxide

2,4-dibromoanisole

n-butyllithium

trimethylborate

→

4-methoxybromobenzene

Disolventes

tetrahydrofuran

acetic acid

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe reaction mixture was then warmed to 0° C.
2. 2
   workup.STIRRINGThe reaction mixture was stirred at room temperature for 30 min
3. 3
   workup.STIRRINGto stir 12 h at room temperature
4. 4
   OtroThe reaction was quenched with 1 N HCl
5. 5
   Extracciónextracted with ethylacetate (100×3)
6. 6
   Secadothe combined organic phases were dried over Na2SO4
7. 7
   Filtraciónfiltered
8. 8
   Otroevaporated under reduced pressure
9. 9
   OtroPurification by column chromatography

Procedimiento

In a 500 mL round bottom flask was charged 2,4-dibromoanisole (5.0 g, 18.8 mmol) followed by 200 mL of dry tetrahydrofuran under nitrogen. The reaction mixture was then cooled to −78° C., and n-butyllithium (16.11 mL, 22.56 mmol) was added dropwise. The reaction mixture was stirred for 30 min at −78° C. The reaction mixture was then warmed to 0° C. and trimethylborate (2.57 mL, 22.56 mmol) was added dropwise. The reaction mixture was stirred at room temperature for 30 min. 5 mL of glacial acetic acid was added followed by 10 mL of 35% wt. hydrogen peroxide in a drop wise fashion. The reaction was allowed to stir 12 h at room temperature. The reaction was quenched with 1 N HCl, extracted with ethylacetate (100×3) and the combined organic phases were dried over Na2SO4, filtered and evaporated under reduced pressure. Purification by column chromatography yielded 1 g (26%) of 3-hydroxy, 4-methoxybromobenzene (white crystals). (96:4 Hexanes:ethylacetate).

Fuente