Potassium Carbonate → 5,5-dimethyl-hexahydro-1'H-spiro[1,3-dioxane-2,2'-pentalene]-5'-one

HRID 1039969Notes

Reaction equation

HRID 1039969 reaction equation
[CH2:1]1[C@@H:8]2[C@@H:4]([CH2:5][C:6](=[O:9])[CH2:7]2)[CH2:3][C:2]1=[O:10].[CH3:11][C:12]([CH3:17])([CH2:15]O)[CH2:13][OH:14].O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C([O-])([O-])=O.[K+].[K+]>C1(C)C=CC=CC=1>[CH3:11][C:12]1([CH3:17])[CH2:13][O:14][C:6]2([CH2:7][CH:8]3[CH:4]([CH2:3][C:2](=[O:10])[CH2:1]3)[CH2:5]2)[O:9][CH2:15]1

Participants

6

Reactant 4

HCID 11430Potassium CarbonateHCID 31344Neopentyl glycolHCID 521998p-Toluenesulfonic acid monohydrateHCID 178516323HCID 178516323, compound

Product 1

HCID 132475235,5-dimethyl-hexahydro-1'H-spiro[1,3-dioxane-2,2'-pentalene]-5'-oneYield 45.9%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
110 °C

Procedure

To a of solution cis-tetrahydropentalene-2,5-(1H,3H)-dione (2.99 g, 21.6 mmol) and 2,2-dimethylpropane-1,3-diol (2.254 g, 21.6 mmol) in toluene (70 mL) was added p-toluenesulfonic acid monohydrate (0.206 g, 1.08 mmol) and the mixture was heated at 110° C. for 24 hrs with a Dean Stark apparatus. The reaction mixture was cooled to room temperature, poured over solid K2CO3, stirred 5 mins then filtered and concentrated under reduced pressure. The residue was purified by flash chromatography (12 to 100% EtOAc in hexanes) to give 5,5-dimethyltetrahydro-1′H-spiro[1,3-dioxane-2,2′-pentalen]-5′(3′H)-one (2.224 g, 9.92 mmol, 45.8% yield) as a colorless oil which solidified upon standing. MS ESI: [M+H]+ m/z 225.7.

Workup

  1. temperatureThe reaction mixture was cooled to room temperature
  2. filtrationthen filtered
  3. concentrationconcentrated under reduced pressure
  4. customThe residue was purified by flash chromatography (12 to 100% EtOAc in hexanes)

Sources & evidence

ORD record
ord-da32e22ecda349d990d4c372e3eb9827
Source dataset
uspto-grants-2013_10
Patent number
US08551984B2

Reaction notes

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