p-Toluenesulfonic acid → 1,1,3,3,5-Pentamethyl-1,3,3a,4,7,7a-hexahydro-isobenzofuran

HRID 61343Notes

Reaction equation

HRID 61343 reaction equation
O[C:2]([CH:5]1[CH:10]([C:11]([OH:14])([CH3:13])[CH3:12])[CH2:9][CH:8]=[C:7]([CH3:15])[CH2:6]1)([CH3:4])[CH3:3].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[CH3:12][C:11]1([CH3:13])[CH:10]2[CH:5]([CH2:6][C:7]([CH3:15])=[CH:8][CH2:9]2)[C:2]([CH3:4])([CH3:3])[O:14]1

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 89704959HCID 89704959, compound

Product 1

HCID 897054911,1,3,3,5-Pentamethyl-1,3,3a,4,7,7a-hexahydro-isobenzofuranYield 9.4%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

2-[6-(1-Hydroxy-1-methyl-ethyl)-4-methyl-cyclohex-3-enyl]-propan-2-ol (720 g, 3.3 mol, obtained as detailed above) was loaded into a round bottom flask fitted with a Bidwell-Sterling trap and dissolved in toluene (1 L). An acid catalyst p-toluenesulfonic acid (pTSA, 40 g, 0.18 mol) was added and the mixture was heated to reflux. The reflux was maintained for 1.5 hours. Water was collected in the Bidwell-Sterling trap during this period. GC analysis indicated the completion of the reaction. The resulting mixture was reduced in volume and purified by fractional distillation to provide 1,1,3,3,5-pentamethyl-1,3,3a,4,7,7a-hexahydro-isobenzofuran (60 g, 9% yield).

Workup

  1. customfitted with a Bidwell-Sterling trap
  2. temperaturethe mixture was heated to reflux
  3. temperatureThe reflux was maintained for 1.5 hours
  4. customWater was collected in the Bidwell-Sterling trap during this period
  5. customthe completion of the reaction
  6. distillationpurified by fractional distillation

Sources & evidence

ORD record
ord-98d7dfe109594061b8317995a1527c38
Source dataset
uspto-grants-2016_09
Patent number
US09441185B2

Reaction notes

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