Reaktion #2648

Reaktionsgleichung

lithium hydroxide monohydrate

(-)-acetic acid cis-4-(tetrahydro-pyran-2-yloxy)-cyclopent-2-enyl ester

tert-butyl methyl ether

water

→

title compound

Ausbeute 93.0%

(+)-cis-4-(tetrahydro-pyran-2-yloxy)-cyclopent-2-enol

Ausbeute 93.0%

Lösungsmittel

chloroform

THF methanol water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONdilute
2. 2
   ExtraktionExtract with tert-butyl methyl ether (2×10 mL)
3. 3
   TrocknenCombine the organic extracts, dry over anhydrous magnesium sulfate
4. 4
   Filtrationfilter
5. 5
   Einengenconcentrate under vacuum
6. 6
   SonstigePurify the residue by flash chromatography (silica gel, 2.5 g, 1.7×2.5 cm column, 50% ethyl acetate/hexane, 150 mL)

Vorschrift

Dissolve (-)-acetic acid cis-4-(tetrahydro-pyran-2-yloxy)-cyclopent-2-enyl ester (106 mg, 0.47 mmol, prepared in example 11) in THF/methanol/water (1.5/0.5/0.5 mL). Add lithium hydroxide monohydrate (0.57 mmol) with stirring. After stirring for about 3 hours at room temperature, dilute the reaction with tert-butyl methyl ether (10 mL) and water (10 mL). Extract with tert-butyl methyl ether (2×10 mL). Combine the organic extracts, dry over anhydrous magnesium sulfate, filter and concentrate under vacuum. Purify the residue by flash chromatography (silica gel, 2.5 g, 1.7×2.5 cm column, 50% ethyl acetate/hexane, 150 mL) to provide the title compound (80 mg, 93% yield), [α]20D =+9.9°, (c=0.98, chloroform).

Quelle