Hydrochloric Acid → 3,4,6,7,8,8a-Hexahydro-2H-1-benzopyran

HRID 73640Notes

Reaction equation

HRID 73640 reaction equation
[H-].C([Al+]CC(C)C)C(C)C.O=[C:12]1[C:17]([CH2:18][CH2:19][C:20]([O:22]CC)=O)=[CH:16][CH2:15][CH2:14][CH2:13]1.Cl>C1COCC1.CCOCC>[O:22]1[CH:12]2[C:17](=[CH:16][CH2:15][CH2:14][CH2:13]2)[CH2:18][CH2:19][CH2:20]1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 109871781-Cyclohexene-1-propanoic acid, 6-oxo-, ethyl esterHCID 21225700Diisobutylaluminumhydride2×

Product 1

HCID 665774673,4,6,7,8,8a-Hexahydro-2H-1-benzopyran

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

A solution of 48 mL diisobutylaluminum hydride (1.0 M in cyclohexane) was cooled to −78° C. and a solution of 2.335 g ethyl 3-(6-oxocyclohex-1-en-1-yl)propanoate in 48 mL THF was added. The reaction was warmed to 0° C. and stirred for one hour, then warmed to RT and stirred for one more hour. The reaction was not complete at this point, so 10 mL additional diisobutylaluminum hydride solution was added the reaction was and stirred at RT for two hours. The reaction was then cooled to −78° C. and then 25 mL 6 M HCl was added dropwise. After the addition was complete, the reaction was allowed to return to RT and was stirred overnight. The reaction was diluted with 200 mL Et2O then washed 2× with water, then with brine. The organic layer was dried over Na2SO4 then filtered, concentrated, and purified on silica gel to provide the title compound.

Workup

  1. temperaturewarmed to RT
  2. stirringstirred for one more hour
  3. additionwas added the reaction
  4. stirringstirred at RT for two hours
  5. temperatureThe reaction was then cooled to −78° C.
  6. additionAfter the addition
  7. customto return to RT
  8. stirringwas stirred overnight
  9. washthen washed 2× with water
  10. dry with materialThe organic layer was dried over Na2SO4
  11. filtrationthen filtered
  12. concentrationconcentrated
  13. custompurified on silica gel

Sources & evidence

ORD record
ord-4803a34230644141b26d4097fea8270d
Source dataset
uspto-grants-2014_09
Patent number
US08829196B2

Reaction notes

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