Diethyl Ether → 2,2-Dimethylcyclopent-4-ene-1,3-dione

HRID 2357016Notes

Reaction equation

HRID 2357016 reaction equation
[CH3:1][C:2]1([CH3:9])[C:6](=[O:7])[CH2:5][CH2:4][C:3]1=[O:8].C(OCC)C>CO.CCCCCC.[Cu](Br)Br>[CH3:1][C:2]1([CH3:9])[C:6](=[O:7])[CH:5]=[CH:4][C:3]1=[O:8]

Participants

6

Reactant 2

HCID 3283Diethyl EtherHCID 197631,3-Cyclopentanedione, 2,2-dimethyl-

Product 1

HCID 45746952,2-Dimethylcyclopent-4-ene-1,3-dioneYield 65%

Reagents, catalysts & solvents 3

HCID 24611Copper bromide (CuBr2)CatalystHCID 887MethanolSolventHCID 8058HexaneSolvent

Procedure

Copper (II) bromide (63.4 g, 0.28 mol) was added to a stirred solution of the dione 2 (17.9 g, 0.14 mol) in methanol (280 ml) at room temperature, under an atmosphere of nitrogen. The reaction was heated under reflux for 90 minutes and then cooled to room temperature. The mixture was then filtered through celite, washing with dichloromethane (3×250 ml) and evaporated in vacuo. Flash chromatography (SiO2, 50% diethyl ether in hexane) gave the enedione 3 (11.3 g, 91.0 mmol, 64%) as a yellow oil; δH (300 MHz, CDCl3) 7.22 (2H, s, CH═CH), 1.17 (3H, s, CH3), 1.15 (3H, s, CH3); δC (75.5 MHz, CDCl3) 207.7 (s), 147.1 (d), 46.4 (s), 19.5 (q).

Workup

  1. temperatureThe reaction was heated
  2. temperatureunder reflux for 90 minutes
  3. filtrationThe mixture was then filtered through celite
  4. washwashing with dichloromethane (3×250 ml)
  5. customevaporated in vacuo

Sources & evidence

ORD record
ord-7641ae064db54c19a66a9d5904327093
Source dataset
uspto-grants-2010_07
Patent number
US07759399B2

Reaction notes

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