Reaktion #56720

Reaktionsgleichung

THF

ethyl cyanoacetate

1-methylcyclopropane-methanol

PCC

→

ester

Ausbeute 26.2%

2-Cyano-3-(1-methyl-cyclopropyl)-acrylic acid ethyl ester

Ausbeute 26.2%

Lösungsmittel

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationThe mixture was filtered through a 1 cm plug of silica gel under vacuum
2. 2
   Waschenrinsed with Et2O
3. 3
   EinengenThe filtrate was concentrated to ca. 5 mL total volume
4. 4
   Sonstigepartitioned between Et2O and sat. aq. NaHCO3
5. 5
   SonstigeThe phases were separated
6. 6
   Waschenthe organic phase washed with brine
7. 7
   Trocknendried (MgSO4)
8. 8
   Einengenconcentrated

Vorschrift

To 1-methylcyclopropane-methanol (Aldrich, 1.13 mL, 11.6 mmol) in 50 mL CH2Cl2 was added neutral alumina (2.5 g) and then PCC (2.5 g, 11.6 mmol), and the mixture stirred 3 h at ambient temperature. The mixture was filtered through a 1 cm plug of silica gel under vacuum, and rinsed with Et2O. The filtrate was concentrated to ca. 5 mL total volume. To the residue was added THF (10 mL), ethyl cyanoacetate (1.2 mL, 11.3 mmol), piperidine (5 drops), and finally acetic acid (5 drops). The whole was stirred at ambient temperature overnight, then partitioned between Et2O and sat. aq. NaHCO3. The phases were separated and the organic phase washed with brine, dried (MgSO4), and concentrated. Flash chromatography of the residue (10→15% EtOAc/hexanes) provided 0.53 g (25%) of the ester as a colorless oil that crystallized on standing. Anal. Calcd for C10H13NO2: C, 67.02; H, 7.31; N, 7.82. Found: C, 66.86; H, 7.47; N, 7.70.

Quelle