3,5-Dimethylcyclohex-2-en-1-one → HCID 23529876, compound

HRID 2307094Notes

Reaction equation

HRID 2307094 reaction equation
[CH:1]([Mg]Br)=[CH2:2].[CH3:5][C:6]1[CH2:11][CH:10]([CH3:12])[CH2:9][C:8](=[O:13])[CH:7]=1>C(=O)=O.CC(C)=O.C1COCC1.Cl[Cu]>[CH3:5][C:6]1([CH:1]=[CH2:2])[CH2:11][CH:10]([CH3:12])[CH2:9][C:8](=[O:13])[CH2:7]1

Participants

6

Reactant 2

HCID 142913,5-Dimethylcyclohex-2-en-1-oneHCID 178418507HCID 178418507, compound

Product 1

HCID 23529876HCID 23529876, compoundYield 52%

Reagents, catalysts & solvents 3

HCID 62652Cuprous chlorideCatalystHCID 8028TetrahydrofuranSolvent2×HCID 18522661Acetone cardiceSolvent

Procedure

A 1M solution of vinylmagnesium bromide in THF (90 ml, 90 mmol) was cooled in dry ice-acetone bath to −20° C. in an inert atmosphere and CuCl (4.45 g, 45 mmol) was added in one portion. The mixture was stirred for 30 min and a solution of 3,5-dimethyl-2-cyclohexen-1-one (41) (3.73 g, 30 mmol) in THF (40 ml) was added dropwise keeping the reaction temperature at −20° C. The cooling bath was removed and the reaction mixture was allowed to reach room temperature for 2 h. Saturated aqueous NH4Cl (50 ml) was added thoroughly while cooling with ice bath. Hexane (150 ml) was then added and the aqueous layer was separated and extracted with hexane (2100 ml). The combined organic extracts were washed with 20% aqueous acetic acid (100 ml) and with saturated aqueous NaHCO3 (3200 ml). The extract was dried over MgSO4, filtered and evaporated. The crude product was purified by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 20:1) to give 42 (2.4 g, 52%) as a colorless oil. 1H-NMR (CDCl3, TMS): 0.99 (3H, d, 6 Hz, 5-CH3); 1.11 (3H, s, 3-CH3); 1.2-2.6 (7H, m, ring protons); 4.94 and 5.01 (total 2H, both d, 17 and 10.5 Hz, CH2═) and 5.64 ppm (1H, dd, 17 and 11 Hz, ═CH).

Workup

  1. additionwas added in one portion
  2. customat −20° C
  3. customThe cooling bath was removed
  4. waitto reach room temperature for 2 h
  5. additionSaturated aqueous NH4Cl (50 ml) was added thoroughly
  6. temperaturewhile cooling with ice bath
  7. additionHexane (150 ml) was then added
  8. customthe aqueous layer was separated
  9. extractionextracted with hexane (2100 ml)
  10. washThe combined organic extracts were washed with 20% aqueous acetic acid (100 ml) and with saturated aqueous NaHCO3 (3200 ml)
  11. dry with materialThe extract was dried over MgSO4
  12. filtrationfiltered
  13. customevaporated
  14. customThe crude product was purified by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 20:1)

Sources & evidence

ORD record
ord-2400bc20f5ea421bb8e983362f856b56
Source dataset
uspto-grants-2004_12
Patent number
US06828462B2

Reaction notes

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