Reacción #455736

Ecuación de reacción

citric acid

2-Bromobenzoic acid

diisopropyl amine

n-BuLi

TMSCl

→

2-Bromo-6-(trimethylsilyl)benzoic acid

Rendimiento 35.0%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturato slowly warm to -30° C.
2. 2
   workup.STIRRINGstirred for 15 min
3. 3
   ExtracciónThe mixture was extracted with two 100 mL portions of ether, which
4. 4
   Lavadowashed three times with sat aq NaHCO3 solution
5. 5
   Extracciónextracted with three 100 mL portions of ether
6. 6
   Secadodried (MgSO4)
7. 7
   Concentraciónconcentrated
8. 8
   OtroThe crude product was purified by recrystallization from ether/hexanes
9. 9
   Otrothe desired product was recovered as a white solid in 35% yield

Procedimiento

2-Bromobenzoic acid (30.15 g, 150 mmol), THF (400 mL), and diisopropyl amine (33.4 g, 330 mmol) were stirred under nitrogen and cooled to -78° C. 10M n-BuLi in hexanes (31 mL, 0.31 mol) was then added dropwise, followed by the dropwise addition of TMSCl (17.4 g, 160 mmol). The mixture was allowed to slowly warm to -30° C., stirred for 1 h, then was poured into 25% citric acid (100 mL) and stirred for 15 min. The mixture was extracted with two 100 mL portions of ether, which were combined and washed three times with sat aq NaHCO3 solution. The bicarbonate solution was acidified with 25% citric acid and extracted with three 100 mL portions of ether. These extracts were combined, dried (MgSO4), and concentrated. The crude product was purified by recrystallization from ether/hexanes, and the desired product was recovered as a white solid in 35% yield. m.p. 139-141° C.

Fuente