1,4-Dibromobenzene → 1,4-Di-2-ethylhexylbenzene

HRID 1748945Notes

Reaction equation

HRID 1748945 reaction equation
[Mg].[CH2:2]([CH:4]([CH2:7][CH2:8][CH2:9][CH3:10])[CH2:5]Br)[CH3:3].[CH2:11]([CH:13]([CH2:17][CH2:18]CC)[CH2:14][Mg]Br)[CH3:12].Br[C:22]1C=CC(Br)=C[CH:23]=1>CCOCC.Cl[Ni]1(Cl)[P](C2C=CC=CC=2)(C2C=CC=CC=2)CCC[P]1(C1C=CC=CC=1)C1C=CC=CC=1>[CH3:3][CH2:2][CH:4]([C:7]1[CH:23]=[CH:22][CH:10]=[CH:9][CH:8]=1)[CH2:5][CH2:14][CH:13]([CH2:17][CH3:18])[CH2:11][CH3:12]

Participants

7

Reactant 4

HCID 78041,4-DibromobenzeneHCID 868042-Ethylhexyl bromideHCID 5462224MagnesiumHCID 178443576HCID 178443576, compound

Product 1

HCID 867199061,4-Di-2-ethylhexylbenzeneYield 58%

Reagents, catalysts & solvents 2

HCID 178418745HCID 178418745, compoundCatalystHCID 3283Diethyl EtherSolvent3×

Procedure

A 500 ml two-necked flask equipped with a reflux condenser attached to a nitrogen gas inlet was charged with 10.1 g (0.422 mol) of magnesium turnings. After heating the reaction mixture for 3 minutes under vacuum and cooling it to room temperature, 200 mL of dry Et2O was filled and then 54.3 g (0.281 mol) of 2-ethylhexyl bromide in 50 mL dry ether was added dropwise. The solution was refluxed for 3 hours and cooled to room temperature. The prepared 2-ethylhexylmagnesium bromide solution was added dropwise, over 1 h, to an ice-cooled and stirring mixture of 1,4-dibromobenzene (24.5 g, 0.104 mol) and Ni(dppp)Cl2 (0.564 g, 1.04 mmol) in dry ether (300 mL). The cooling bath was removed and the temperature was increased to room temperature. The reaction solution was then refluxed overnight, cooled to 0° C. and carefully quenched with water (50 mL), followed by 2N HCl (300 mL). After separation of the organic layer, the organic layer was washed with water (300 mL) two times and dried with anhydrous sodium sulfate and evaporated in vacuo. Column chromatography (silica gel, hexane) yielded the pure compound 20a (18.2 g, 58%). 1H NMR (CDCl3): δ 0.84-0.92 (12H, m), 1.25-1.35 (16H, m), 1.50-1.58 (2H, m), 2.50 (4H, d), 7.04 (4H, s). MS (EI): calcd, 302.5. found M+, 302.3.

Workup

  1. customA 500 ml two-necked flask equipped with a reflux condenser
  2. customattached to a nitrogen gas inlet
  3. temperatureAfter heating the reaction mixture for 3 minutes under vacuum
  4. temperatureThe solution was refluxed for 3 hours
  5. temperaturecooled to room temperature
  6. temperaturecooled
  7. customThe cooling bath was removed
  8. temperaturethe temperature was increased to room temperature
  9. temperatureThe reaction solution was then refluxed overnight
  10. temperaturecooled to 0° C.
  11. customcarefully quenched with water (50 mL)
  12. customAfter separation of the organic layer
  13. washthe organic layer was washed with water (300 mL) two times
  14. dry with materialdried with anhydrous sodium sulfate
  15. customevaporated in vacuo

Sources & evidence

ORD record
ord-b605c960839240d4bae3339998974c34
Source dataset
uspto-grants-2015_10
Patent number
US09153785B2

Reaction notes

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