Ethyl formate → 4-Hydroxy-3-isobutyl-but-3-en-2-one

HRID 1676105Notes

Reaction equation

HRID 1676105 reaction equation
CC([O-])(C)C.[K+].[CH2:7]([O:9]C=O)[CH3:8].[CH3:12][CH:13]([CH3:19])[CH2:14][CH2:15][C:16](=[O:18])C>C1COCC1.CC(=O)OCC>[OH:18][CH:16]=[C:15]([CH2:14][CH:13]([CH3:19])[CH3:12])[C:7](=[O:9])[CH3:8]

Participants

6

Reactant 3

HCID 8025Ethyl formate2×HCID 80345-Methyl-2-hexanoneHCID 23665647Potassium tert-butoxide

Product 1

HCID 866457654-Hydroxy-3-isobutyl-but-3-en-2-oneYield 65.6%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
10 °C

Procedure

To a solution of KOtBu (50 g, 446 mmol) in THF (400 mL) is added during 30 min ethylformate (92 g, 1.25 mol). Strong gas evolution occurs. The mixture is cooled during the addition with a water bath at 10° C. After complete addition, the mixture is stirred until the gas evolution ceases (15 min). The mixture is cooled with ice at 0° C. and a mixture of 5-methyl-2-hexanone (34.25 g, 300 mmol) and ethylformate (41 g, 0.55 mol) is added slowly during 30 min. The mixture is stirred for 15 h, diluted with EA (500 mL) and washed with 1 N aq. HCl (100 mL), 1 M aq. NaH2PO4 solution (100 mL) and brine (100 mL). The organic extract is dried (MgSO4), filtered and evaporated to give crude 4-hydroxy-3-isobutyl-but-3-en-2-one (28 g) which is used without further purification; LC-MS: tR=0.80 min, [M+1]=143.39.

Workup

  1. additionAfter complete addition
  2. temperatureThe mixture is cooled with ice at 0° C.
  3. additionis added slowly during 30 min
  4. stirringThe mixture is stirred for 15 h
  5. washwashed with 1 N aq. HCl (100 mL), 1 M aq. NaH2PO4 solution (100 mL) and brine (100 mL)
  6. extractionThe organic extract
  7. dry with materialis dried (MgSO4)
  8. filtrationfiltered
  9. customevaporated

Sources & evidence

ORD record
ord-2447fc9d9d0f49c4852706056eac354e
Source dataset
uspto-grants-2011_08
Patent number
US08003800B2

Reaction notes

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