反应详情

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.

1. waitThe mixture was left
2. extractionExtraction with diethyl ether (200 mL)
3. washwashing with a saturated solution of NaCl (100 mL, 3×)
4. dry with materialdrying (Na2SO4)
5. additionadding of hydroquinone (10 mg)
6. concentrationconcentrating
7. customafforded 6.44 g of the crude compound
8. concentrationto the product fraction, concentration
9. customdrying under vacuum (0.2 mbar, 1 h)