Triisopropyl borate → (5-Cyano-2-methylphenyl)boronic acid

HRID 1408846Notes

Reaction equation

HRID 1408846 reaction equation
Br[C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[CH3:10])[C:5]#[N:6].[Li]CCCC.[B:16](OC(C)C)([O:21]C(C)C)[O:17]C(C)C>C1COCC1>[C:5]([C:4]1[CH:7]=[CH:8][C:9]([CH3:10])=[C:2]([B:16]([OH:21])[OH:17])[CH:3]=1)#[N:6]

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 140048403-Bromo-4-methylbenzonitrileHCID 178418339Butyllithium

Product 1

HCID 53216743(5-Cyano-2-methylphenyl)boronic acidYield 27.8%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred solution of 3-bromo-4-methylbenzonitrile (3.5 g, 17.86 mmol) in dry THF at −78° C. was added n-BuLi (2N, 10.71 mL) dropwise. The mixture was stirred for 15 min., and added triisopropyl borate (6.71 g, 35.71 mmol). The reaction flask was kept in the cooling bath for 30 min., and at room temperature for 3 hours. The solvent was removed, and the residue was dissolved in ether. The organic phase was washed with 1N HCl solution and water, dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo, and the residue was crystallized from a mixture of CH2Cl2 and hexane to give 5-cyano-2-methylphenylboronic acid (800 mg, 20%). 1H-NMR (CDCl3 400 MHz): δ7.50-7.78 (m, 2H), 7.30 (d, 1H), 2.42 (s, 3H).

Workup

  1. waitThe reaction flask was kept in the cooling bath for 30 min.
  2. waitat room temperature for 3 hours
  3. customThe solvent was removed
  4. dissolutionthe residue was dissolved in ether
  5. washThe organic phase was washed with 1N HCl solution and water
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. concentrationThe filtrate was concentrated in vacuo
  9. customthe residue was crystallized from a mixture of CH2Cl2 and hexane

Sources & evidence

ORD record
ord-3dac17cb61f345ce8566a08aa68f6b88
Source dataset
uspto-grants-2014_12
Patent number
US08921359B2

Reaction notes

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