1-Pentene, 5-bromo- → 5-Methyl-2-(pent-4-enyl)benzaldehyde

HRID 501715Notes

Reaction equation

HRID 501715 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[CH:9]([O:12]C)OC.Br[CH2:15][CH2:16][CH2:17][CH:18]=[CH2:19]>C1COCC1.C([Li])CCC>[CH3:8][C:5]1[CH:6]=[CH:7][C:2]([CH2:19][CH2:18][CH2:17][CH:16]=[CH2:15])=[C:3]([CH:4]=1)[CH:9]=[O:12]

Participants

5

Reactant 2

HCID 707041-Pentene, 5-bromo-HCID 667049941-Bromo-2-(dimethoxymethyl)-4-methylbenzene

Product 1

HCID 866223425-Methyl-2-(pent-4-enyl)benzaldehydeYield 10%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 178418339ButyllithiumSolvent

Procedure

Step AI (4): 1-Bromo-2-(dimethoxymethyl)-4-methylbenzene (615 mg, 2.51 mmol) was dissolved in THF (10 mL) under N2 atmosphere at −78° C. n-Butyllithium (1.6 M, 3.1 mL) was added and the reaction mixture was stirred for 30 min. 5-Bromopent-1-ene (0.31 mL, 2.64 mmol) was added. The reaction mixture was warmed to rt and stirred for 18 h. The reaction was quenched with the addition of HCl (1.0 N) and was further stirred at rt for 1 h. The reaction mixture was extracted with EtOAc and washed with brine. The combined organic phases were dried over Na2SO4, filtered and concentrated in vacuum. The residue was purified by silica gel chromatography to give 5-methyl-2-(pent-4-enyl)benzaldehyde (45 mg, 10%) as a colorless oil. LC-MS (M+H)+=189.41.

Workup

  1. additionwas added
  2. stirringstirred for 18 h
  3. customThe reaction was quenched with the addition of HCl (1.0 N)
  4. stirringwas further stirred at rt for 1 h
  5. extractionThe reaction mixture was extracted with EtOAc
  6. washwashed with brine
  7. dry with materialThe combined organic phases were dried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated in vacuum
  10. customThe residue was purified by silica gel chromatography

Sources & evidence

ORD record
ord-394294b89f374899bb891608270f8105
Source dataset
uspto-grants-2010_08
Patent number
US07772221B2

Reaction notes

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