Triisopropyl borate → (6-Methoxy-1-benzothiophen-2-yl)boronic acid

HRID 1070317Notes

Reaction equation

HRID 1070317 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[CH:10]=[CH:9][S:8][C:7]=2[CH:11]=1.[Li]CCCC.[B:17](OC(C)C)([O:22]C(C)C)[O:18]C(C)C>C1COCC1>[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[CH:10]=[C:9]([B:17]([OH:22])[OH:18])[S:8][C:7]=2[CH:11]=1

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 136342376-Methoxy-1-benzothiopheneHCID 178418339Butyllithium

Product 1

HCID 10560276(6-Methoxy-1-benzothiophen-2-yl)boronic acidYield 71%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
9 °C

Procedure

To a solution of 6-methoxybenzo[b]thiophene (Graham, S. L., et al. J. Med. Chem. 1989, 32,2548-2554) (18.13 g, 0.111 mol) in 150 mL of anhydrous THF at −60° C. was added n-BuLi (76.2 mL., 0.122 mol. 1.6 M solution in hexanes), dropwise via syringe. After stirring for 30 min, triisopropyl borate (28.2 ml. 0.122 mol) was introduced via syringe. The resulting mixture was allowed to gradually warm to 9° C. and then partitioned between 1.0 N HCl and EtOAc (300 mL each). The layers were separated, and the organicphase was dried over Na2SO4. Concentration in vacuo produced a white solit that was triturated from Et2O/hexanes. Filtration provided 16.4 g (71%) of 6-methoxybenzo[b]thiophene-2-boronic acid as a white solid.

Workup

  1. custompartitioned between 1.0 N HCl and EtOAc (300 mL each)
  2. customThe layers were separated
  3. dry with materialthe organicphase was dried over Na2SO4
  4. concentrationConcentration in vacuo
  5. customproduced a white solit that
  6. customwas triturated from Et2O/hexanes
  7. filtrationFiltration

Sources & evidence

ORD record
ord-8ae70eccfffd47e393643819bf965ade
Source dataset
uspto-grants-2001_06
Patent number
US06251921B1

Reaction notes

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