6-Methyl-5-hepten-2-ol → 3-Isopropyl-6-methyl-2-propenyl-tetrahydro-pyran

HRID 61341

Reaction equation

HRID 61341 reaction equation
[CH3:1][C:2]([CH3:9])=[CH:3][CH2:4][CH2:5][CH:6]([OH:8])[CH3:7].[CH:10](=O)/[CH:11]=[CH:12]/[CH3:13]>C1(C)C=CC(S(O)(=O)=O)=CC=1.C1(C)C=CC=CC=1>[CH:2]([CH:3]1[CH2:4][CH2:5][CH:6]([CH3:7])[O:8][CH:10]1[CH:11]=[CH:12][CH3:13])([CH3:9])[CH3:1]

Participants

5

Reactant 2

HCID 207456-Methyl-5-hepten-2-olHCID 447466Crotonaldehyde2×

Product 1

HCID 1317371733-Isopropyl-6-methyl-2-propenyl-tetrahydro-pyranYield 71.2%

Reagents, catalysts & solvents 2

HCID 6101p-Toluenesulfonic acidCatalystHCID 1140TolueneSolvent

Conditions

Temperature
122 °C

Procedure

6-Methyl-hept-5-en-2-ol (512 g, 3.8 mol, 96%), toluene (750 ml), and p-toluenesulfonic acid (pTSA, 2.6 g) were charged in a flask and heated to 122° C. Crotonaldehyde (350 g, 5 mol) was fed into the mixture for over 3-4 hours at reflux. Water was removed with a Bidwell-Sterling trap. The reaction mixture was aged for 1 hour. Standard addition and gas chromatography (GC) analysis indicated that about 11% of the starting material 6-methyl-hept-5-en-2-ol was left. Additional crotonaldehyde (35 g, 0.5 mol) was added. The reaction mixture was at reflux for another 45 minutes. About 70 ml water was collected and the final temperature was about 118° C. GC analysis indicated that about 8% of the starting material 6-methyl-hept-5-en-2-ol was left. The reaction mixture was quenched with water and wash one time with dilute carbonate solution. The consequent rushover process provided the product 3-isopropyl-6-methyl-2-propenyl-tetrahydro-pyran (493 g) with a boiling point of 109 C at a pressure of 25 mmHg.

Workup

  1. customwas fed into the mixture for over 3-4 hours
  2. temperatureat reflux
  3. customWater was removed with a Bidwell-Sterling trap
  4. additionStandard addition and gas chromatography (GC) analysis
  5. waitwas left
  6. temperatureat reflux for another 45 minutes
  7. customAbout 70 ml water was collected
  8. customwas about 118° C
  9. waitwas left
  10. customThe reaction mixture was quenched with water
  11. washwash one time with dilute carbonate solution

Sources & evidence

ORD record
ord-e755393f054d4b03b6c1b9ab002095bd
Source dataset
uspto-grants-2016_09
Patent number
US09441185B2

Linked notes

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