Reaktion #73258

Reaktionsgleichung

5-(diethoxymethyl)thiophene-3-carbaldehyde

diethyl cyanomethylphosphonate

potassium tert-butoxide

→

(2E)-3-[5-(diethoxymethyl)-3-thienyl]acrylonitrile

Ausbeute 85.3%

Lösungsmittel

THF

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe bath was removed
2. 2
   TemperaturThe reaction was cooled to 0° C.
3. 3
   SonstigeThe reaction was partitioned between water and ethyl acetate
4. 4
   WaschenThe combined extracts were washed with saturated sodium chloride
5. 5
   Trocknendried over magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated
8. 8
   SonstigeThe crude residue was purified by flash column chromatography on silica gel eluting (ethyl acetate:hexane, 1:5)

Vorschrift

To a solution of diethyl cyanomethylphosphonate (100 mg, 0.0008 mol) in THF (2 mL, 0.02 mol) cooled at 0° C. and 1.0 M potassium tert-butoxide in THF (0.8 mL) was added dropwise. The bath was removed and the reaction was warmed to room temperature for 30 minutes. The reaction was cooled to 0° C. and a solution of 5-(diethoxymethyl)thiophene-3-carbaldehyde (170 mg, 0.00079 mol) in THF (2 mL, 0.02 mol) was added drop wise. The reaction was stirred overnight at room temperature. The reaction was partitioned between water and ethyl acetate. The combined extracts were washed with saturated sodium chloride, dried over magnesium sulfate, filtered and concentrated. The crude residue was purified by flash column chromatography on silica gel eluting (ethyl acetate:hexane, 1:5) to give (2E)-3-[5-(diethoxymethyl)-3-thienyl]acrylonitrile as an oil (160 mg, 84.9%). 1H NMR (300 MHz, CDCl3): 7.4-7.0 (m, 3H), 5.65 (m 1H), 4.2 (m, 1H), 3.65 (m, 4H), 1.25 (m, 6H).

Quelle