Iodine → 4-Hexyloxyphenylboronic Acid

HRID 1635753Notes

Reaction equation

HRID 1635753 reaction equation
[Mg].II.[CH2:4]([O:10][C:11]1[CH:16]=[CH:15][C:14](Br)=[CH:13][CH:12]=1)[CH2:5][CH2:6][CH2:7][CH2:8][CH3:9].[B:18](OC)([O:21]C)[O:19]C.S(=O)(=O)(O)O>C(OC1C=CC(Br)=CC=1)CCCCC.C1COCC1>[CH2:4]([O:10][C:11]1[CH:16]=[CH:15][C:14]([B:18]([OH:21])[OH:19])=[CH:13][CH:12]=1)[CH2:5][CH2:6][CH2:7][CH2:8][CH3:9]

Participants

8

Reactant 5

HCID 807IodineHCID 1118Sulfuric AcidHCID 8470Trimethyl borateHCID 520492Benzene, 1-bromo-4-(hexyloxy)-HCID 5462224Magnesium2×

Product 1

HCID 36821484-Hexyloxyphenylboronic Acid

Reagents, catalysts & solvents 2

HCID 520492Benzene, 1-bromo-4-(hexyloxy)-CatalystHCID 8028TetrahydrofuranSolvent3×

Procedure

In an apparatus which had been baked out and blanketed with argon, magnesium turnings (1.89 g; 78 mmol) were treated with a crystal of iodine and covered with dried THF. A few drops of 4-hexyloxybromobenzene were then added to the solution without stirring. The Grignard reaction began very quickly and, while stirring, the 4-hexyloxybromobenzene (total amount: 20 g; 78 mmol) was then added dropwise at such a rate that the mixture boiled gently. During this addition, the mixture was diluted with a little THF (total amount: about 100 ml). The mixture was refluxed for 3 hours (only a few flakes of magnesium remaining in the solution) and subsequently allowed to cool. The Grignard solution was transferred to a 250 ml dropping funnel in a countercurrent of protective gas and added dropwise to a solution of trimethyl borate (8.9 g; 9.6 ml; 86 mmol) in 50 ml of dry THF while stirring at −70° C., resulting in formation of a precipitate. The reaction mixture was allowed to warm to RT overnight and was then introduced while stirring into a mixture of 100 g of ice and 3 ml of concentrated sulfuric acid. The organic phase was separated off, the aqueous phase was extracted 3 times with 100 ml each time of chloroform and the combined organic phases were evaporated. The crude product was subsequently recrystallized from hexane. Product: colorless, wax-like solid (11.28 g; 66%); melting point: 84-87° C.

Workup

  1. customThe Grignard reaction
  2. stirringwhile stirring
  3. additionDuring this addition
  4. temperatureto cool
  5. stirringwhile stirring at −70° C.
  6. customresulting in formation of a precipitate
  7. additionwas then introduced
  8. customThe organic phase was separated off
  9. extractionthe aqueous phase was extracted 3 times with 100 ml each time of chloroform
  10. customthe combined organic phases were evaporated
  11. customThe crude product was subsequently recrystallized from hexane

Sources & evidence

ORD record
ord-476dc803a4a94bb590cf8a64220a5639
Source dataset
uspto-grants-2003_01
Patent number
US06509507B2

Reaction notes

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