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

HRID 1743894Notes

Reaction equation

HRID 1743894 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([F:8])=[CH:4][C:3]=1[CH3:9].C([Li])CCC.C[O:16][B:17](OC)[O:18]C.[OH-].[Na+]>O1CCCC1>[CH3:9][C:3]1[CH:4]=[C:5]([F:8])[CH:6]=[CH:7][C:2]=1[B:17]([OH:18])[OH:16]

Participants

6

Reactant 4

HCID 8470Trimethyl borateHCID 14798Sodium HydroxideHCID 967432-Bromo-5-fluorotolueneHCID 178418339Butyllithium

Product 1

HCID 2734665(4-Fluoro-2-methylphenyl)boronic acidYield 81%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

2-Bromo-5-fluorotoluene (52.9 mmol, 10 g) in 400 ml of tetrahydrofuran was cooled to −78° C. and n-butyllithium (2.5 M, 58.2 mmol) was added. The solution was stirred for 20 minutes, trimethoxy borane (3 eq, 0.16 mol) was added, and the reaction was allowed to warm to room temperature overnight. Sodium hydroxide (60 ml of 1.25 M) was added and the reaction was stirred for 30 minutes. The tetrahydrofuran was removed in vacuo. The remaining aqueous layer was diluted and extracted with diethyl ether. The aqueous layer was adjusted to pH 3 with 2N HCl and extracted with ethyl acetate, which was dried (MgSO4) and concentrated in vacuo to give 6.57 g (81%) of a colorless solid: MS(FAB) m/e (rel. intensity) 154(48), 136(100).

Workup

  1. stirringthe reaction was stirred for 30 minutes
  2. customThe tetrahydrofuran was removed in vacuo
  3. additionThe remaining aqueous layer was diluted
  4. extractionextracted with diethyl ether
  5. extractionextracted with ethyl acetate, which
  6. dry with materialwas dried (MgSO4)
  7. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-43261d9862904bb0a6853c1ede6aaa59
Source dataset
uspto-grants-2006_03
Patent number
US07012094B1

Reaction notes

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