1,4-Cyclohexanedione → 4-Benzylidenecyclohexanone

HRID 67689

Reaction equation

HRID 67689 reaction equation
[Br-].[CH2:2]([P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.C([Li])CCC.[C:33]1(=O)[CH2:38][CH2:37][C:36](=[O:39])[CH2:35][CH2:34]1>C1COCC1.CCCCC>[CH:2](=[C:33]1[CH2:34][CH2:35][C:36](=[O:39])[CH2:37][CH2:38]1)[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1

Participants

6

Reactant 3

HCID 125111,4-CyclohexanedioneHCID 2734970Benzyltriphenylphosphonium bromideHCID 178418339Butyllithium

Product 1

HCID 197051964-BenzylidenecyclohexanoneYield 120%

Reagents, catalysts & solvents 2

HCID 8003PentaneSolventHCID 8028TetrahydrofuranSolvent2×

Procedure

To a mechanically stirred suspension of 15.24 g (0.035 mole) of benzyltriphenylphosphonium bromide in 150 ml of THF there was added first 22 ml of 1.61 N n-butyllithium in pentane and then 5.0 g (0.032 mole) of cyclohexane-1,4-dione, ethylene monoketal in 50 ml of THF. Following 5 hours' heating at reflux the mixture was allowed to cool and was then washed in turn with water and brine. The organic layer was concentrated, and the residue was chromatographed on 1 liter of silica gel, eluting with 20% ethyl acetate in Skellysolve® B, to afford 7.15 g (97%) of 4-benzylidenecyclohexanone, ethylene ketal as an oil, the nmr spectrum of which is in consonance with the structure.

Workup

  1. temperature' heating
  2. temperatureat reflux the mixture
  3. temperatureto cool
  4. washwas then washed in turn with water and brine
  5. concentrationThe organic layer was concentrated
  6. customthe residue was chromatographed on 1 liter of silica gel
  7. washeluting with 20% ethyl acetate in Skellysolve® B

Sources & evidence

ORD record
ord-d5cd9f739af5413aa3c9e451bf0a50a4
Source dataset
uspto-grants-1982_08
Patent number
US04346101

Linked notes

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