3,4-dihydro-2H-pyran → (S)-4-(2-tetrahydropyranyloxy)-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-one

HRID 1079002Notes

Reaction equation

HRID 1079002 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].[O:12]1[CH:17]=[CH:16][CH2:15][CH2:14][CH2:13]1.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>ClCCl>[O:12]1[CH2:17][CH2:16][CH2:15][CH2:14][CH:13]1[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]

Participants

5

Reactant 3

HCID 80803,4-dihydro-2H-pyranHCID 1569974-Hydroxy-3-methyl-2-(prop-2-yn-1-yl)cyclopent-2-en-1-oneHCID 521998p-Toluenesulfonic acid monohydrate

Product 1

HCID 86749753(S)-4-(2-tetrahydropyranyloxy)-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-oneYield 86.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

1 To a solution of (S)-4-hydroxy-3-methyl-2(2-propynyl)cyclopent-2-ene-l-one (20.0 g) in dichloromethane (200 ml) were added with stirring 3,4-dihydro-2H-pyran (12.5 g) and a catalytic amount of p-toluenesulfonic acid hydrate under ice-water cooling, then the solution was stirred at room temperature for 1.5 hours. This solution was partitioned between diethyl ether and brine, and the organic layer was washed twice with brine. The organic layer was dried over anhydrous sodium sulfate, and then the solvent was evaporated under reduced pressure. The resultant residue was subjected to silica gel column chromatography (eluent; n-hexane:ethyl acetate=5:1) to afford (S)-4-(2-tetrahydropyranyloxy)-3-methyl-2-(2-propynyl)cyclopent-2-ene-1-one (27 g, yield 86.6%) pale yellow oil.

Workup

  1. customThis solution was partitioned between diethyl ether and brine
  2. washthe organic layer was washed twice with brine
  3. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  4. customthe solvent was evaporated under reduced pressure

Sources & evidence

ORD record
ord-ac631a4e566946a08daecfcd438f6f52
Source dataset
uspto-grants-1996_08
Patent number
US05550260

Reaction notes

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