Imidazole → (S)-4-tert-butyldimethylsilyloxy-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-one

HRID 1078996Notes

Reaction equation

HRID 1078996 reaction equation
[OH:1][C@H:2]1[CH2:6][C:5](=[O:7])[C:4]([CH2:8][C:9]#[CH:10])=[C:3]1[CH3:11].N1C=CN=C1.[C:17]([Si:21]([CH3:24])([CH3:23])Cl)([CH3:20])([CH3:19])[CH3:18].C(O)(=O)C(O)=O>CN(C)C=O>[Si:21]([O:1][C@H:2]1[CH2:6][C:5](=[O:7])[C:4]([CH2:8][C:9]#[CH:10])=[C:3]1[CH3:11])([C:17]([CH3:20])([CH3:19])[CH3:18])([CH3:24])[CH3:23]

Participants

6

Reactant 4

HCID 795ImidazoleHCID 971Oxalic AcidHCID 28928tert-Butyldimethylsilyl chlorideHCID 1569974-Hydroxy-3-methyl-2-(prop-2-yn-1-yl)cyclopent-2-en-1-one

Product 1

HCID 11043662(S)-4-tert-butyldimethylsilyloxy-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-oneYield 86.3%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent2×

Procedure

1 (S)-4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-ene-1-one (50.0 g) was dissolved in dry dimethylformamide (600 ml), and imidazole (27.3 g) was added to the dimethylformamide solution. Tert-butyldimethylchlorosilane (55.3 g) was added to the solution under ice-water cooling and the resulting mixture was allowed to react for 2 hours, then for 13 hours at 20° C. The reaction solution was poured into an aqueous oxalic acid solution under ice-water cooling, and extracted three times with diethyl ether (200 ml). The ether layers were combined, and the combined layer was washed with saturated aqueous sodium bicarbonate solution and brine in sequence. After dried over anhydrous sodium sulfate, the solvent was evaporated under reduced pressure. The resultant residue was subjected to distillation under reduced pressure to afford (S)-4-tert-butyldimethylsilyloxy-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-one (76.0 g, yield 86.0%) as a pale yellow oil.

Workup

  1. customto react for 2 hours
  2. extractionextracted three times with diethyl ether (200 ml)
  3. washthe combined layer was washed with saturated aqueous sodium bicarbonate solution and brine in sequence
  4. dry with materialAfter dried over anhydrous sodium sulfate
  5. customthe solvent was evaporated under reduced pressure
  6. distillationThe resultant residue was subjected to distillation under reduced pressure

Sources & evidence

ORD record
ord-4a4e797b8f314bd1a2c4889ba247d509
Source dataset
uspto-grants-1996_08
Patent number
US05550260

Reaction notes

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