Reacción #70328

Ecuación de reacción

1,2-dibromotetrachloroethane

TMDA

sec-BuLi

3-cyclopropyl-5-fluorobenzoic acid

→

expected compound

2-bromo-5-cyclopropyl-3-fluorobenzoic acid

Disolventes

THF

THF

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGstirred for additional 20 min
2. 2
   OtroA white suspension was obtained
3. 3
   OtroThe cooling bath was removed and at −20° C. water (30 mL) and diethyl ether (30 mL)
4. 4
   workup.ADDITIONwere added
5. 5
   OtroThe organic layer was separated
6. 6
   Extracciónextracted with diethyl ether
7. 7
   LavadoThe organic phase was washed with water and brine
8. 8
   Otrodried
9. 9
   Filtraciónfiltered
10. 10
    Concentraciónconcentrated in vacuo

Procedimiento

To a solution of TMDA (1.3 ml, 8.61 mmol) in dry THF (9 mL) under inert atmosphere at −65° C., a 1.4M solution of sec-BuLi (8 ml, 11.20 mmol) was added dropwise. Then a solution of 3-cyclopropyl-5-fluorobenzoic acid (0.69 g, 3.83 mmol) in dry THF (3 mL) was added dropwise and stirred for 1 h. Then a solution of 1,2-dibromotetrachloroethane (5 g, 15.48 mmol) in dry THF (11 mL) was added dropwise for 1 h and stirred for additional 20 min. A white suspension was obtained. The cooling bath was removed and at −20° C. water (30 mL) and diethyl ether (30 mL) were added. The organic layer was separated and the aqueous phase was acidified (until pH: 1) using a 2N aqueous solution of HCl (13 mL needed) and extracted with diethyl ether. The organic phase was washed with water and brine, dried, filtered and concentrated in vacuo to afford a mixture 1:1 of the expected compound and starting material (38% yield), which was used without further purification

Fuente