1,2-Dibromoethane → HCID 67370279, compound

Participants

Reaction Steps

Magnesium turnings (9.53 g, 0.39 mol) were covered with dry diethyl ether (50 ml) at room temperature under nitrogen. 1,2-Dibromoethane (0.5 ml) was added in one portion. As soon as a visible reaction had started (bubbling), magnetic stirring was switched on and a solution of 1,4-dibromobutane (50 g, 0.225 mol) in dry diethyl ether (360 ml) was added at a rate such as to maintain a constant reflux (1 hour). The reaction was further refluxed for 1 hour before cooling in an ice-water bath. Ethyl 4,5-dimethyl-4-hexenoate (26.5 g, 0.156 mol) in dry diethyl ether (30 ml) was added dropwise. Then the reaction was warmed up to room temperature and the reaction was refluxed for 1 hour. It was recooled in an ice-water bath before adding a saturated aqueous ammonium chloride solution (250 ml, slowly). After warming up to room temperature and shaking vigorously, the phases were separated. The organic phase was washed with aqueous saturated bicarbonate (250 ml) and water (500 ml). Each aqueous phase was re-extracted with diethyl ether (250 ml). Combined extracts were dried over anhydrous sodium sulfate. The product was purified by column chromatography on silica gel (eluting with heptanes/ethyl acetate 11:1 to 3:1) followed by bulb-to-bulb distillation (110° C./1 mbar). 22.62 g of the title compound (99.6% pure, 0.122 mol, 78%) were obtained.

Provenance & Evidence