Sulfuric Acid → 3-Benzylcyclopent-2-en-1-one

HRID 1934320Notes

Reaction equation

HRID 1934320 reaction equation
C(O[C:4]1[CH2:8][CH2:7][C:6](=[O:9])[CH:5]=1)C.[CH2:10]([Mg]Cl)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.OS(O)(=O)=O>C1COCC1>[CH2:10]([C:4]1[CH2:8][CH2:7][C:6](=[O:9])[CH:5]=1)[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 897773-Ethoxycyclopent-2-en-1-oneHCID 178418336HCID 178418336, compound

Product 1

HCID 118299173-Benzylcyclopent-2-en-1-oneYield 35%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of 3-ethoxy-2-cyclopenten-1-one (5 g, 0.89 mol) in THF (70 mL) was added at room temperature to a solution of 2M benzyl magnesium chloride (800 mL) under N2 and stirred for 6 h. The resulting mixture was poured into a solution of 30% H2SO4 and stirred for 5 h. The resulting organic layer was separated, and the aqueous layer was extracted with several portions of ether. The combined organic layer was dried (MgSO4), and concentrated in vacuo to give the title compound (3.1 g, 35%) as a colorless oil. NMR(CDCl3):3.45(s, 2H, benzylic protons), 5.83 (bs, 1H, olefinic proton), 7.22 (m, 5H, aromatic protons).

Workup

  1. stirringstirred for 5 h
  2. customThe resulting organic layer was separated
  3. extractionthe aqueous layer was extracted with several portions of ether
  4. dry with materialThe combined organic layer was dried (MgSO4)
  5. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-542254b89be743c088432dd9c1cdb5ad
Source dataset
uspto-grants-2002_05
Patent number
US06384031B1

Reaction notes

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