Reacción #653337

Ecuación de reacción

hydrochloric acid

triisopropyl borate

n-butyl lithium

4-bromotoluene

→

4-methylphenyl boric acid

Rendimiento 73.4%

Disolventes

THF

hexane

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGthe solution was stirred overnight
2. 2
   workup.STIRRINGstirred for 30 min
3. 3
   Extracciónthe reaction solution was extracted twice with diethyl ether
4. 4
   Lavadowashed thrice with water
5. 5
   Secadodried over anhydrous magnesium sulfate
6. 6
   workup.DISTILLATIONThe solvent was distilled off
7. 7
   Otrothe residue was recrystallized from about 1,000 ml of toluene

Procedimiento

To a mixture of 4-bromotoluene (743 mmol) and 500 ml of THF was added dropwise 500 ml of a solution of n-butyl lithium (corresponding to 780 mmol) in hexane at −78° C. in 1.6 hours, and stirred at the same temperature for 1.5 hours. To this solution was added dropwise 200 ml of a solution of triisopropyl borate (1,486 mmol) in THF, the solution was gradually warmed up to room temperature, and then the solution was stirred overnight. After 750 ml of 7.3% hydrochloric acid was added and stirred for 30 min, the reaction solution was extracted twice with diethyl ether, washed thrice with water, and then dried over anhydrous magnesium sulfate. The solvent was distilled off and the residue was recrystallized from about 1,000 ml of toluene to give a white solid of 4-methylphenyl boric acid (545 mmol).

Fuente