4-Bromostyrene → (Z)-3-hexenyl 2-oxo-2-(4-vinylphenyl)acetate

Beteiligte Stoffe

Reaktionsschritte

A Grignard reagent prepared from 4-bromostyrene (6.95 g, 38.0 mmol) and magnesium (0.97 g, 39.9 mmol) in THF (100 mL) was added dropwise (during a period of 20 min) to a stirred solution of bis[(Z)-3-hexenyl]oxalate (9.20 g, 36.2 mmol) in THF (35 mL) at −60° C. The mixture was left warming to room temperature and poured into a mixture of ice (100 g) and a saturated solution of NH4Cl (100 mL). Extraction with diethyl ether (200 mL, 2×), washing with a saturated solution of NaCl (50 mL, 4×, pH 7), drying (Na2SO4) and concentrating afforded 11.47 g of the crude compound as a brownish oil. Bulb-to-bulb distillation of 8.68 g of the crude product (0.06 mbar, 60° C.) and column chromatography (SiO2, heptane/ether 95:5, then 1:1, then pure ether) gave 3.53 g (50%) of an oil.

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