Citric Acid → (RS)-4-t-butyldimethylsilyloxy-3-methyl-2-(2,2,2-trifluoroethyl)cyclopent-2-en-1-one

HRID 1379944Notes

Reaction equation

HRID 1379944 reaction equation
[OH:1][CH:2]1[CH2:6][C:5](=[O:7])[C:4]([CH2:8][C:9]([F:12])([F:11])[F:10])=[C:3]1[CH3:13].N1C=CN=C1.[C:19]([Si:23]([CH3:26])([CH3:25])Cl)([CH3:22])([CH3:21])[CH3:20].C(O)(=O)CC(CC(O)=O)(C(O)=O)O>CN(C)C=O>[Si:23]([O:1][CH:2]1[CH2:6][C:5](=[O:7])[C:4]([CH2:8][C:9]([F:10])([F:11])[F:12])=[C:3]1[CH3:13])([C:19]([CH3:22])([CH3:21])[CH3:20])([CH3:26])[CH3:25]

Participants

6

Reactant 4

HCID 311Citric AcidHCID 795ImidazoleHCID 28928tert-Butyldimethylsilyl chlorideHCID 22283798(RS)-2-methyl-3-(2,2,2-trifluoroethyl)-4-oxocyclopent-2-en-1-ol

Product 1

HCID 22908402(RS)-4-t-butyldimethylsilyloxy-3-methyl-2-(2,2,2-trifluoroethyl)cyclopent-2-en-1-oneYield 90%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

After 10 g of (RS)-4-hydroxy-3-methyl-2-(2,2,2-trifluoroethyl)cyclopent-2-en-1-one and 4.2 g of imidazole were dissolved in 100 ml of dry dimethylformamide, 8.54 g of t-butyldimethylchlorosilane was added to the solution at an ambient temperature. After stirring at an ambient temperature for 12 hours, the reaction solution was added to 5% aqueous citric acid under ice-water cooling, and extracted three times with diethyl ether. The combined organic layer was washed successively with a saturated sodium hydrogencarbonate solution and a saturated sodium chloride solution, and dried with anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the residue was subjected to silica gel column chromatography to yield 14.3 g of (RS)-4-t-butyldimethylsilyloxy-3-methyl-2-(2,2,2-trifluoroethyl)cyclopent-2-en-1-one. Yield 90% (Eluent: n-hexane/ethyl acetate=5/1 (v/v))

Workup

  1. extractionextracted three times with diethyl ether
  2. washThe combined organic layer was washed successively with a saturated sodium hydrogencarbonate solution
  3. dry with materiala saturated sodium chloride solution, and dried with anhydrous magnesium sulfate
  4. customAfter removal of the solvent under reduced pressure

Sources & evidence

ORD record
ord-96b0dc9639b64652989dbe9595cc6175
Source dataset
uspto-grants-1997_09
Patent number
US05672779

Reaction notes

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