Reaktion #48107

Reaktionsgleichung

hydrochloric acid

triisopropyl borate

1-bromo-4-cyclopropyl-benzene

→

product

4-Cyclopropyl-phenylboronic acid

Lösungsmittel

hexane

THF

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONis added
2. 2
   TemperaturThe solution is warmed to −20° C.
3. 3
   TemperaturThe reaction mixture is further warmed to room temperature
4. 4
   Sonstigethe organic phase is separated
5. 5
   ExtraktionThe aqueous phase is extracted with ethyl acetate
6. 6
   Trocknenthe combined organic phases are dried (sodium sulphate)
7. 7
   SonstigeThe solvent is evaporated
8. 8
   Waschenthe residue is washed with a mixture of ether and cyclohexane

Vorschrift

2.5 M nButyllithium in hexane (14.5 mL) is added dropwise to 1-bromo-4-cyclopropyl-benzene (5.92 g) in THF (14 mL) and toluene (50 mL) chilled to −70° C. The resultant solution is stirred at −70° C. for 30 min before triisopropyl borate (8.5 mL) is added. The solution is warmed to −20° C. and then treated with 4 M aqueous hydrochloric acid (15.5 mL). The reaction mixture is further warmed to room temperature and then the organic phase is separated. The aqueous phase is extracted with ethyl acetate and the combined organic phases are dried (sodium sulphate). The solvent is evaporated and the residue is washed with a mixture of ether and cyclohexane to give the product as a colorless solid.

Quelle