Ethyl bromoacetate → Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester

HRID 1019264Notes

Reaction equation

HRID 1019264 reaction equation
[C:1]1([P:7]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.Br[CH2:21][C:22]([O:24][CH2:25][CH3:26])=[O:23]>C1C=CC=CC=1>[CH2:25]([O:24][C:22]([CH:21]=[P:7]([C:1]1[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1)([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1)=[O:23])[CH3:26]

Participants

4

Reactant 2

HCID 7748Ethyl bromoacetateHCID 11776Triphenylphosphine

Product 1

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl esterYield 80.4%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

To a solution of triphenylphosphine (26.20 g, 100 mmol) in benzene (150 ml) was added ethyl bromoacetate (16.70 g, 100 mmol) at 0-5° C. The mixture was kept at room temperature for 16 h. The resulting phosphonium salt was filtered, washed with benzene (100 ml), and dried. To a solution of the solid in water (200 ml) was added benzene (200 ml), followed by 10% NaOH solution (100 ml). The organic layer was separated, and the aqueous layer was extracted with benzene (200 ml). The combined organic layers were washed with water (100 ml) and brine (100 ml), concentrated to 50 ml in vacuo, and poured onto hexane (200 ml). The precipitate was filtered and dried to afford the desired phosphorane (28.00 g, 80%) as a colorless solid. mp 128-130° C. 4-Oxocyclohexylideneacetic acid ethyl ester. To a solution of 1,4-cyclohexanedione (5.00 g, 44.64 mmol) in benzene (100 ml) was added the ylide (15.55 g, 44.68 mole). The mixture was heated under reflux for 12 h. After removal of the solvent by evaporation, the residue was purified by flash chromatography (silica gel, 5% ethyl acetate in hexanes) to afford the ketone ester (5.80 g, 71%) as a colorless oil. 1H NMR (500 MHz, CDCl3) δ1.26 (t, J=6.4 Hz, 3H), 2.42-2.50 (m, 4H,), 2.60-2.66 (m, 2H), 3.12-3.20 (m, 2H), 4.16 (q, J=6.4 Hz, 2H), 5.86 (s, 1H).

Workup

  1. filtrationThe resulting phosphonium salt was filtered
  2. washwashed with benzene (100 ml)
  3. customdried
  4. additionTo a solution of the solid in water (200 ml) was added benzene (200 ml)
  5. customThe organic layer was separated
  6. extractionthe aqueous layer was extracted with benzene (200 ml)
  7. washThe combined organic layers were washed with water (100 ml) and brine (100 ml)
  8. concentrationconcentrated to 50 ml in vacuo
  9. additionpoured onto hexane (200 ml)
  10. filtrationThe precipitate was filtered
  11. customdried

Sources & evidence

ORD record
ord-bf4b9e4bcbb7495383ae1061c7ea6a70
Source dataset
uspto-grants-2002_11
Patent number
US06486199B1

Reaction notes

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