Reacción #637499

Ecuación de reacción

Ethyl acetate

Diethyl methoxy borane

4-Bromopyridine

N-Butyllithium

→

Diethyl (4-pyridyl borane)

Disolventes

brine

ether

ether

ether

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added drop wise
2. 2
   workup.STIRRINGThe ethereal solution was stirred for 30 minutes at −40° C.
3. 3
   Temperaturathen cooled to −70° C
4. 4
   workup.ADDITIONwas added drop wise
5. 5
   Temperaturato warm to room temperature over night
6. 6
   Otrothe organic layer was separated
7. 7
   SecadoThis was dried over magnesium sulfate
8. 8
   Filtraciónfiltered
9. 9
   Otroevaporated
10. 10
    Otroto yield a brown tar
11. 11
    OtroThe product was purified by column chromatography on silica
12. 12
    Lavadoeluted with toluene

Procedimiento

N-Butyllithium (1.6M in hexanes, 20 ml) was added to dry ether (100 ml) and cooled to −40° C. under nitrogen. The solution was stirred and a solution of 4-Bromopyridine (32 mmols) dissolved in dry ether was added drop wise. The ethereal solution was stirred for 30 minutes at −40° C. then cooled to −70° C. Diethyl methoxy borane (4.6 ml) dissolved in dry ether (50 ml) was added drop wise and the mixture was allowed to warm to room temperature over night. Ethyl acetate (100 ml) and brine (70 ml) were added to the resulting brown solution and the organic layer was separated. This was dried over magnesium sulfate, filtered and evaporated to yield a brown tar. The product was purified by column chromatography on silica eluted with toluene to yield (0.94 g, 6.4 mmols) of Diethyl (4-pyridyl borane) (I) as a white solid.

Fuente