Triisopropyl borate → (5-Bromo-2-cyclopropylphenyl)boronic acid

HRID 40477

Reaction equation

HRID 40477 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([CH:9]2[CH2:11][CH2:10]2)=[C:6](I)[CH:7]=1.C([Mg]Cl)(C)C.C([O:20][B:21](OC(C)C)[O:22]C(C)C)(C)C>O1CCCC1>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([CH:9]2[CH2:11][CH2:10]2)=[C:6]([B:21]([OH:22])[OH:20])[CH:7]=1

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 580615715-Bromo-2-cyclopropyliodobenzeneHCID 178418918HCID 178418918, compound

Product 1

HCID 58061455(5-Bromo-2-cyclopropylphenyl)boronic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 5-bromo-2-cyclopropyliodobenzene (5.67 g, 0.018 mol) in anhydrous tetrahydrofuran (32 ml) at −78° C. is added isopropylmagnesium chloride (9.5 ml, 0.019 mol, 2M solution in THF) at such a rate as to maintain a temperature below −60° C. Once addition is complete the reaction mixture is stirred for 20 minutes at this temperature and then allowed to warm to room temperature and stir for an additional 2 hours. The solution is then cooled again to −78° C. and triisopropylborate (8.3 ml, 0.036 mol) is added dropwise. After stirring at this temperature for 10 minutes the solution is allowed to warm to room temperature and stir for an additional 2 hours. After quenching with 2M aqueous hydrochloric acid (20 ml) the reaction mixture is diluted with distilled water then extracted with ethyl acetate (×3). Organic fractions are combined, washed with distilled water and brine, then dried over magnesium sulfate and concentrated in vacuo. The crude solid is azeotroped with toluene (×3) then triturated with isohexane to afford 5-bromo-2-cyclopropylphenyl boronic acid as a cream solid.

Workup

  1. temperatureto maintain a temperature below −60° C
  2. additionOnce addition
  3. stirringstir for an additional 2 hours
  4. temperatureThe solution is then cooled again to −78° C.
  5. stirringAfter stirring at this temperature for 10 minutes the solution
  6. temperatureto warm to room temperature
  7. stirringstir for an additional 2 hours
  8. customAfter quenching with 2M aqueous hydrochloric acid (20 ml) the reaction mixture
  9. additionis diluted with distilled water
  10. extractionthen extracted with ethyl acetate (×3)
  11. washwashed with distilled water and brine
  12. dry with materialdried over magnesium sulfate
  13. concentrationconcentrated in vacuo
  14. customThe crude solid is azeotroped with toluene (×3)
  15. customthen triturated with isohexane

Sources & evidence

ORD record
ord-00f1a68a4e23463aa152e0743d43893b
Source dataset
uspto-grants-2013_09
Patent number
US08530388B2

Linked notes

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