p-Bromopropiophenone → 1-Bromo-4-(but-1-en-2-yl)benzene

HRID 855275Notes

Reaction equation

HRID 855275 reaction equation
[Li][CH2:2]CCC.[CH3:6][CH2:7][C:8]([C:10]1[CH:15]=[CH:14][C:13]([Br:16])=[CH:12][CH:11]=1)=O>CCOCC.[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[Br:16][C:13]1[CH:14]=[CH:15][C:10]([C:8](=[CH2:2])[CH2:7][CH3:6])=[CH:11][CH:12]=1

Participants

5

Reactant 2

HCID 66312p-BromopropiophenoneHCID 178418339Butyllithium

Product 1

HCID 221662261-Bromo-4-(but-1-en-2-yl)benzeneYield 32.9%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 3283Diethyl EtherSolvent2×

Procedure

To a solution of n-BuLi (2.79 ml, 1.6M solution in hexane, 4.46 mmol) in ether was added solid methyltriphenylphosphonium bromide (1.59 g, 4.46 mmol) in three portions. The mixture was stirred at rt for 4 h, and then a solution of 4-bromopropio-phenone (1.00 g, 4.69 mmol) in ether was added and the mixture was gently refluxed overnight. The mixture was filtered and the filtrate was washed with water and brine, dried (MgSO4), filtered and concentrated in vacuo to give a residue which was purified by flash column chromatography to give 1-bromo-4-(1-methylenepropyl)-benzene (310 mg, 31%) as a colorless oil. 1H NMR (CDCl3, 300 MHz): δ 7.45 (d, J=9.0 Hz, 2H), 7.28 (d, J=9.0 Hz, 2H), 5.26 (m, 1H), 5.07 (m, 1H), 2.48 (q, J=7.5 Hz, 2H), 1.09 (t, J=7.5 Hz, 3H).

Workup

  1. waitthe mixture was gently refluxed overnight
  2. filtrationThe mixture was filtered
  3. washthe filtrate was washed with water and brine
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered
  6. concentrationconcentrated in vacuo
  7. customto give a residue which
  8. customwas purified by flash column chromatography

Sources & evidence

ORD record
ord-5ab36d444bd44ff38036a546149ba0d5
Source dataset
uspto-grants-2007_08
Patent number
US07259183B2

Reaction notes

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