Reaktion #82852

Reaktionsgleichung

methyl 3-oxo-6-octenoate

5-(2-nitrovinyl)-1,3-benzodioxole

ethyl acetate hexane

→

title compound

Ausbeute 82.0%

Methyl 2-(4-hexenoyl)-4-nitro-3-(1,3-benzodioxole-5-yl)butyrate

Ausbeute 82.0%

Lösungsmittel

isopropanol

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeconsumption of ketoester
2. 2
   EinengenThe solution was concentrated in vacuo and flash
3. 3
   Sonstigechromatographed on silica gel eluting with 18% ethyl acetate in hexane

Vorschrift

A solution of methyl 3-oxo-6-octenoate (502 mg, 2.95 mmol) in 10 mL of isopropanol was added to a solution of 5-(2-nitrovinyl)-1,3-benzodioxole (712 mg, 3.69 mmol) in 10 mL THF, then DBU (22 μL, 0.15 mmol) was added. The resulting reddish solution was stirred at room temperature for 20 minutes. TLC (ethyl acetate-hexane, 1:3) indicated complete consumption of ketoester. The solution was concentrated in vacuo and flash chromatographed on silica gel eluting with 18% ethyl acetate in hexane to produce 879 mg (2.42 mmol, 82%) of the title compound as a mixture of diastereomers in a 1:1 ratio. 1H NMR (CDCl3, 300 MHz) δ 1.55-1.66 (m, 3H), 2.02-2.17 (br m, 1H), 2.20-2.37 (m, 1.5H), 2.49-2.76 (m, 1.5H), 3.57 (s, 1.5H), 3.74 (s, 1.5H), 3.97 (d, J=7.5H, 0.5H) and 4.05 (d, J=8 Hz, 0.5H), 4.10-4.20 (m, 1H), 4.68-4.82 (m, 2H), 5.06-5.52 (m, 2H), 5.95 (2s, 2H), 6.65 (m, 1H), 6.68 (br s, 1H), 6.75 (d, 7.5 Hz, 1H). MS (DCI/NH3) m/e 381 (M+NH4)+.

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