Reaktion #717753

Reaktionsgleichung

hydroquinone

(E)-bis(3,7-dimethylocta-2,6-dien-1-yl)oxalate

NH4Cl

4-bromostyrene

magnesium

→

oil

Ausbeute 21.0%

(E)-3,7-dimethylocta-2,6-dien-1-yl 2-oxo-2-(4-vinylphenyl)acetate

Ausbeute 21.0%

Lösungsmittel

heptane ether

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITThe mixture was left
2. 2
   ExtraktionExtraction with diethyl ether (200 mL)
3. 3
   Waschenwashing with a saturated solution of NaCl (100 mL, 3×)
4. 4
   Trocknendrying (Na2SO4)
5. 5
   workup.ADDITIONadding of hydroquinone (10 mg)
6. 6
   Einengenconcentrating
7. 7
   Sonstigeafforded 6.44 g of the crude compound
8. 8
   Einengento the product fraction, concentration
9. 9
   Sonstigedrying under vacuum (0.2 mbar, 1 h)

Vorschrift

A Grignard reagent prepared from 4-bromostyrene (2.78 g, 15.2 mmol) and magnesium (0.39 g, 15.9 mmol) in THF (23 mL) was added dropwise (during 20 min) to a stirred solution of (E)-bis(3,7-dimethylocta-2,6-dien-1-yl)oxalate (5.00 g, 13.8 mmol) in THF (40 mL) at −60° C. The mixture was left warming to room temperature, and then poured into a mixture of ice (70 g) and a saturated solution of NH4Cl (60 mL). Extraction with diethyl ether (200 mL), washing with a saturated solution of NaCl (100 mL, 3×), drying (Na2SO4), adding of hydroquinone (10 mg) and concentrating afforded 6.44 g of the crude compound. Repetitive column chromatography (SiO2, heptane/ether 9:1 and 98:2), addition of hydroquinone to the product fraction, concentration and drying under vacuum (0.2 mbar, 1 h) gave 0.90 g (21%) of an oil.

Quelle