Triisopropyl borate → 2-Chloro-5-ethoxybenzeneboronic acid

HRID 1639933Notes

Reaction equation

HRID 1639933 reaction equation
C([Li])CCC.[Cl:6][C:7]1[CH:12]=[CH:11][C:10]([O:13][CH2:14][CH3:15])=[CH:9][C:8]=1I.[B:17](OC(C)C)([O:22]C(C)C)[O:18]C(C)C>CCCCCC.C1COCC1.CCOC(C)=O.Cl>[Cl:6][C:7]1[CH:12]=[CH:11][C:10]([O:13][CH2:14][CH3:15])=[CH:9][C:8]=1[B:17]([OH:22])[OH:18]

Participants

7

Reactant 3

HCID 21531Triisopropyl borateHCID 588637541-Chloro-2-iodo-4-ethoxybenzeneHCID 178418339Butyllithium

Product 1

HCID 223094612-Chloro-5-ethoxybenzeneboronic acidYield 59%

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolventHCID 8058HexaneSolventHCID 21866389Hydrogen chloride-ethyl acetateSolvent

Procedure

Add, dropwise, 5.5 mL (8.8 mmol) of a 1.6N solution of butyllithium in hexane in the space of 30 min to a solution of 2.38 g (8.4 mmol) of 1-chloro-2-iodo-4-ethoxybenzene in 50 mL of anhydrous THF cooled under argon to −78° C. After 2 h at −70° C., add 1.74 g (9.2 mmol) of triisopropyl borate and stir the reaction mixture for 3 h at room temperature, then distribute in 200 mL of EtOAc/HCl aq 5N 1:1 mixture. Wash the organic phase with 50 mL of water, dry over Na2SO4 and concentrate under reduced pressure. Purify the residue obtained by silica gel column chromatography, eluting with a DCM/methanol gradient from 0 to 10% of methanol. After concentration under reduced pressure, we obtain 990 mg of (2-chloro-5-ethoxyphenyl)boronic acid, in the form of oil.

Workup

  1. additionAdd
  2. washWash the organic phase with 50 mL of water
  3. dry with materialdry over Na2SO4
  4. concentrationconcentrate under reduced pressure
  5. customPurify the residue
  6. customobtained by silica gel column chromatography
  7. washeluting with a DCM/methanol gradient from 0 to 10% of methanol
  8. concentrationAfter concentration under reduced pressure, we

Sources & evidence

ORD record
ord-99047844078746a49e7a9e42ad5ab3c2
Source dataset
uspto-grants-2012_02
Patent number
US08110579B2

Reaction notes

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