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

HRID 2204521ノート

反応式

HRID 2204521 の反応式
[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

参加物

7

反応物 4

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

生成物 1

HCID 10877556cis-Ethyl 4-hydroxy-2-methylcyclopent-2-enecarboxylate収率 46.6%

試薬・触媒・溶媒 2

HCID 887Methanol溶媒HCID 3283Diethyl Ether溶媒

実験手順

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).

後処理

  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

出典と根拠

ORDレコード
ord-abc3039d7b7d47cf9542e3dbbc19f2a0
出典データセット
uspto-grants-2016_06
特許番号
US09365579B2

反応ノート

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