Potassium Carbonate → HCID 57316274, compound

HRID 1457791Notes

Reaction equation

HRID 1457791 reaction equation
[CH3:1][C@H:2]1[CH2:7][C:6](=[O:8])[CH2:5][C:4](=[O:9])[C@@H:3]1[C:10]([O:12][CH:13]1[CH:18]([CH:19]([CH3:21])[CH3:20])[CH2:17][CH2:16][CH:15]([CH3:22])[CH2:14]1)=[O:11].[C:23](=O)([O-])[O-].[K+].[K+]>CO.C12(CS(O)(=O)=O)C(C)(C)C(CC1)CC2=O>[CH3:23][O:8][C:6]1[CH2:7][C@H:2]([CH3:1])[C@@H:3]([C:10]([O:12][C@H:13]2[C@H:18]([CH:19]([CH3:21])[CH3:20])[CH2:17][CH2:16][C@@H:15]([CH3:22])[CH2:14]2)=[O:11])[C:4](=[O:9])[CH:5]=1

Participants

5

Reactant 2

HCID 11430Potassium CarbonateHCID 86753439HCID 86753439, compound

Product 1

HCID 57316274HCID 57316274, compoundYield 713.6%

Reagents, catalysts & solvents 2

HCID 18462Bicyclo[2.2.1]heptane-1-methanesulfonic acid, 7,7-dimethyl-2-oxo-, (1S)-CatalystHCID 887MethanolSolvent

Conditions

Temperature
23 °C

Procedure

A solution of (1R, 3R, 4S)-p-menth-3-yl (1R, 2S)-2-methyl-4,6- dioxocyclohexanecarboxylate (2, 24.0 g, 77.8 mmol, 1 equiv) in methanol (300 mL) was treated with camphorsulfonic acid (ca. 800 mg, 3.9 mmol, 0.05 equiv) and the resulting solution was stirred at 23° C. for 12 h. The reaction mixture was neutralized by the addition of solid potassium carbonate (1.08 g, 7.78 mmol, 0.10 equiv) and the resulting suspension was filtered and the filtrate was concentrated. The residue was concentrated from toluene (2×15 mL) and then was purified by flash column chromatography (20% ethyl acetate-hexanes) to afford (1R, 3R, 4S)-p-menth-3-yl (1R, 6S)-4-methoxy-6-methyl-2-oxo-3-cyclohexene-1-carboxylate (4) as a white solid (mp 78°-80° C., 17.9 g, 71%). The regioisomeric enone, (1R, 3R, 4S)-p-menth-3-yl (1R, 6S)-2-methoxy-6-methyl-4-oxo-2-cyclohexene-1-carboxylate (5) was isolated in separate fractions and was resubjected to the reaction conditions to establish the equilibrium mixture of enones, in which the desired product 4 is strongly favored.

Workup

  1. filtrationthe resulting suspension was filtered
  2. concentrationthe filtrate was concentrated
  3. concentrationThe residue was concentrated from toluene (2×15 mL)
  4. customwas purified by flash column chromatography (20% ethyl acetate-hexanes)

Sources & evidence

ORD record
ord-0e52d76cfe354a30a12c24ae1db79509
Source dataset
uspto-grants-1998_12
Patent number
US05849750

Reaction notes

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