Hydrochloric Acid → 5-(4-Chlorophenyl)-2-methylphenylboronic acid

HRID 43329Notes

Reaction equation

HRID 43329 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:9]=[CH:10][C:11]([CH2:15]C)=[C:12](Br)[CH:13]=2)=[CH:4][CH:3]=1.C([Li])CCC.C[O:23][B:24](OC)[O:25]C.Cl>C1COCC1>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:9]=[CH:10][C:11]([CH3:15])=[C:12]([B:24]([OH:25])[OH:23])[CH:13]=2)=[CH:4][CH:3]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 594459053-Bromo-4'-chloro-4-ethylbiphenylHCID 178418339Butyllithium

Product 1

HCID 594459235-(4-Chlorophenyl)-2-methylphenylboronic acidYield 73%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

5-(4-chlorophenyl)-2-ethyl-1-bromobenzene (10 g, 0.03 mol) is dissolved in THF (250 ml), and the temperature is brought to −78° C. n-Butyllithium (1.33 molar solution in hexanes, 34.6 ml,) is added dropwise over 30 minutes, maintaining the temperature at around −78° C. The reaction mixture is stirred for one and half hours, then trimethylborate (4.9 g, 0.05 mol) is added dropwise and the reaction mixture stirred for two hours. A solution of 2N aqueous hydrochloric acid (100 ml) is added dropwise, and once the addition is complete the mixture is stirred for two hours. The mixture is concentrated to remove most of the tetrahydrofuran, then diluted with water and extracted with diethyl ether. The organic extracts are washed with water and brine, combined, dried over anhydrous sodium sulfate, filtered and the filtrate evaporated in vacuo. The residue is further purified by flash column chromatography on silica gel, eluting with 7% ethyl acetate in hexane to give 5-(4-chloro-phenyl)-2-methylphenylboronic acid (5.4 g).

Workup

  1. customis brought to −78° C.
  2. additionis added dropwise over 30 minutes
  3. stirringthe reaction mixture stirred for two hours
  4. additiononce the addition
  5. stirringis stirred for two hours
  6. concentrationThe mixture is concentrated
  7. customto remove most of the tetrahydrofuran
  8. additiondiluted with water
  9. extractionextracted with diethyl ether
  10. washThe organic extracts are washed with water and brine
  11. dry with materialdried over anhydrous sodium sulfate
  12. filtrationfiltered
  13. customthe filtrate evaporated in vacuo
  14. customThe residue is further purified by flash column chromatography on silica gel
  15. washeluting with 7% ethyl acetate in hexane

Sources & evidence

ORD record
ord-a02d86a5b47748efaf55a000c3a59226
Source dataset
uspto-grants-2013_09
Patent number
US08536351B2

Reaction notes

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