The monomer formed was extracted with three portions of 20 ml of ethyl ether, and the organic phase obtained
was washed with saturated solution of NaHSO3 and dried with anhydrous MgSO4. A concentration step was carried
out by evaporation of the solvent at low pressure, and the oil obtained was purified in a column loaded with silica gel containing 1% (w/v) of triethylamine employing the mixture hexane:ethyl ether as eluent.
Working at these conditions,2.85 g of E were obtained in a form of a pale yellow oil (yield of 76%)