Reaktion #469308

Reaktionsgleichung

triisopropylborate

4-bromobiphenyl

n-butyllithium

→

4-Biphenylboronic acid

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 10 minutes
2. 2
   Sonstigepartitioned between EtOAc (50 mL) and 10% aqueous HCl (50 mL)
3. 3
   SonstigeThe aqueous layer was separated
4. 4
   Extraktionextracted with more EtOAc
5. 5
   WaschenThe combined organic layers were washed with brine
6. 6
   Trocknendried over Na2SO4
7. 7
   Einengenconcentrated
8. 8
   Sonstigeto give a crude product which

Vorschrift

4-Biphenylboronic acid was prepared differently than described in the literature (see Yabroff, D. L.; Branch, G. E.; Bettman, B. J. Am. Chem. Soc. 1934, 56, 1850-1857). To a solution of 4-bromobiphenyl (2.00 g, 8.58 mmol) in THF (20 mL) at −78° C. was added n-butyllithium (4.0 mL of 2.5 M in hexanes) in a slow stream via syringe. After 15 minutes, triisopropylborate (3.0 mL, 13 mmol) was added in a slow stream via syringe. After 10 minutes, the resultant homogeneous solution was allowed to warm to ambient temperature over 45 minutes and partitioned between EtOAc (50 mL) and 10% aqueous HCl (50 mL). The aqueous layer was separated and extracted with more EtOAc. The combined organic layers were washed with brine, dried over Na2SO4 and concentrated to give a crude product which was triturated with hexanes to yield 1.53 g (90%) of 4-biphenylboronic acid as a white solid.

Quelle