Ammonium Chloride → cis-Ethyl 4-hydroxy-2-methylcyclopent-2-enecarboxylate

HRID 1854370Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1854370
[CH3:1][C:2]1[CH:3]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH2:4][C:5](=[O:7])[CH:6]=1.O.O.O.O.O.O.O.[Cl-].[Ce+3].[Cl-].[Cl-].[BH4-].[Na+].[NH4+].[Cl-]>CCOCC.CO>[OH:7][C@@H:5]1[CH2:4][C@H:3]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[C:2]([CH3:1])=[CH:6]1

Komponenten

7

Edukt 4

HCID 25517Ammonium ChlorideHCID 4311764Sodium borohydrideHCID 11332690Ethyl 2-methyl-4-oxocyclopent-2-ene-1-carboxylateHCID 21585214Cerium trichloride heptahydrate

Produkt 1

HCID 10877556cis-Ethyl 4-hydroxy-2-methylcyclopent-2-enecarboxylateAusbeute 46,6 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 887MethanolLösungsmittelHCID 3283Diethyl EtherLösungsmittel

Versuchsvorschrift

A round-bottom flask was charged with ethyl 2-methyl-4-oxocyclopent-2-enecarboxylate (2.04 g, 12.1 mmol, Preparation #CC.1), MeOH (30 mL), and cerium(III) chloride heptahydrate (5.65 g, 15.2 mmol) followed by portion-wise addition of sodium borohydride (0.574 g, 15.2 mmol). The suspension was stirred at room temperature over about 16 h. Saturated aqueous NH4Cl solution (50 mL) was added. The mixture was stirred for about 10 min and Et2O (60 mL) was added. The layers were separated and the aqueous layer was extracted with Et2O (3×30 mL). The combined organic layers were washed with saturated aqueous NaHCO3, dried over anhydrous MgSO4, filtered, and concentrated to dryness under reduced pressure. The residue was purified via silica gel chromatography eluting with 20-60% EtOAc/pentane to yield cis-ethyl 4-hydroxy-2-methylcyclopent-2-enecarboxylate (0.96 g, 46%): 1H NMR (400 MHz, CDCl3) δ 5.77-5.71 (m, 1H), 4.63 (m, 1H), 4.28-4.11 (m, 2H), 3.27-3.20 (m, 1H), 2.59 (bs, 1H), 2.41-2.30 (m, 1H), 2.00 (d, J=14.2 Hz, 1H), 1.79 (d,=1.2 Hz, 3H), 1.30 (t, J=7.1 Hz, 3H) and trans-ethyl 4-hydroxy-2-methylcyclopent-2-enecarboxylate (0.69 g, 33%): 1H NMR (400 MHz, CDCl3) δ 5.63 (dd, J=1.8, 3.4 Hz, 1H), 4.98 (m, 1H), 4.20-4.11 (m, 2H), 3.60-3.53 (m, 1H), 2.57 (ddd, J=4.4, 7.1, 13.9 Hz, 1H), 1.98 (ddd, J=3.5, 8.4, 13.9 Hz, 1H), 1.80 (d, J=1.4, 3H), 1.46 (bs, 1H), 1.27 (t, J=7.1 Hz, 3H).

Aufarbeitung

  1. stirringThe mixture was stirred for about 10 min
  2. customThe layers were separated
  3. extractionthe aqueous layer was extracted with Et2O (3×30 mL)
  4. washThe combined organic layers were washed with saturated aqueous NaHCO3
  5. dry with materialdried over anhydrous MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated to dryness under reduced pressure
  8. customThe residue was purified via silica gel chromatography
  9. washeluting with 20-60% EtOAc/pentane

Quellen und Nachweise

ORD-Eintrag
ord-840c6c5b8f104f399806e1a8ba9beb63
Quelldatensatz
uspto-grants-2015_02
Patentnummer
US08962629B2

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