反応 #56720

反応方程式

THF

ethyl cyanoacetate

1-methylcyclopropane-methanol

PCC

→

ester

収率 26.2%

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

収率 26.2%

溶媒

CH2Cl2

反応条件

後処理

1. 1
   ろ過The mixture was filtered through a 1 cm plug of silica gel under vacuum
2. 2
   洗浄rinsed with Et2O
3. 3
   濃縮The filtrate was concentrated to ca. 5 mL total volume
4. 4
   その他partitioned between Et2O and sat. aq. NaHCO3
5. 5
   その他The phases were separated
6. 6
   洗浄the organic phase washed with brine
7. 7
   乾燥dried (MgSO4)
8. 8
   濃縮concentrated

実験手順

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.

出典