Triisopropyl borate → (4-Fluoro-2-methylphenyl)boronic acid

HRID 1403575Notes

Reaction equation

HRID 1403575 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([F:8])=[CH:4][C:3]=1[CH3:9].C([Li])CCC.CC([O:18][B:19](OC(C)C)[O:20]C(C)C)C>C1COCC1.[OH-].[Na+]>[F:8][C:5]1[CH:6]=[CH:7][C:2]([B:19]([OH:20])[OH:18])=[C:3]([CH3:9])[CH:4]=1

Participants

6

Reactant 3

HCID 21531Triisopropyl borateHCID 967432-Bromo-5-fluorotolueneHCID 178418339Butyllithium

Product 1

HCID 2734665(4-Fluoro-2-methylphenyl)boronic acidYield 52%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 14798Sodium HydroxideSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of 1-bromo-4-fluoro-2-methylbenzene (5 g, 26.45 mmol) in THF (100 mL) was added n-butyllithium (12.7 mL) dropwise at −78° C. Tris(propan-2-yl)borate (10 g, 53.17 mmol) was added dropwise and the reaction was stirred overnight at −78° C. in a liquid nitrogen bath. The resulting solution was diluted with aqueous sodium hydroxide (1N, 30 mL) and extracted with ether (2×50 mL). The aqueous layers were combined and adjusted to pH 3 with HCl (3N), extracted with ethyl acetate (3×50 mL), and the organic layers were combined and concentrated in vacuo to give (4-fluoro-2-methylphenyl)boronic acid as a white solid (2.1 g, 52%).

Workup

  1. extractionextracted with ether (2×50 mL)
  2. extractionextracted with ethyl acetate (3×50 mL)
  3. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-ac7737b826e8406e80b9ef39368d65df
Source dataset
uspto-grants-2014_12
Patent number
US08912188B2

Reaction notes

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