Reaktion #2029764

Reaktionsgleichung

sodium cyclopentadienide

methyl 3-iodopropionate

→

methyl 3-cylopenta-1,3-dienylpropionate

methyl 3-cylopenta-1,4-dienylpropionate

Ausbeute 46.0%

Lösungsmittel

diethyl ether

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe above compounds were prepared
2. 2
   SonstigeThe resulting reaction mixture
3. 3
   workup.WAITstored at −20° C. for a further 15 hours
4. 4
   SonstigeThe resulting red suspension was quenched with 1 M ammonium chloride solution (800 mL)
5. 5
   Extraktionthe organic phase was extracted with diethyl ether (5×400 mL)
6. 6
   WaschenThe combined organic layer was washed with 1 M ammonium chloride solution (2×500 mL)
7. 7
   Trocknendried (anhydrous sodium sulfate)
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated in vacuo
10. 10
    SonstigeThe crude oil was purified by flash chromatography on silica using 5% ethyl acetate in iso-hexane

Vorschrift

The above compounds were prepared using a modified literature method (16). A 2.0 M solution of sodium cyclopentadienide in tetrahydrofuran (105.10 mL, 210.28 mmol) was added dropwise over 15 minutes to a stirred solution of methyl 3-iodopropionate (45.00 g, 210.28 mmol) in anhydrous diethyl ether (280 mL) and anhydrous tetrahydrofuran (200 mL) under nitrogen at −78° C. The resulting reaction mixture was stirred at −78° C. for 2 hours and then stored at −20° C. for a further 15 hours. The resulting red suspension was quenched with 1 M ammonium chloride solution (800 mL), and the organic phase was extracted with diethyl ether (5×400 mL). The combined organic layer was washed with 1 M ammonium chloride solution (2×500 mL) and dried (anhydrous sodium sulfate), filtered and concentrated in vacuo. The crude oil was purified by flash chromatography on silica using 5% ethyl acetate in iso-hexane to afford methyl 3-cylopenta-1,3-dienylpropionate (1-alkylCp) and methyl 3-cylopenta-1,4-dienylpropionate (2-alkylCp) (14.72 g, 96.72 mmol, 46%) as yellow liquids in a 1.2:1 ratio.

Quelle