To a solution of the product of Step 1, above, (1.0 g, 3.4 mmol) in 10 ml THF at -20° C. was added a 1M solution of potassium t-butoxide in THF (3.73 ml, 3.73 mmol) over 15 minutes. After 30 minutes at -20° C., cis-1,4-dichlorobut-2-ene (0.393 ml, 3.73 mmol) was added dropwise and the reaction was warmed to room temperature. After 20 minutes the reaction was cooled to -20° C. and treated with potassium t-butoxide in THF (3.73 ml, 3.73 mmol). The reaction was allowed to warm to room temperature, then was heated at 50° C. for 30 minutes and quenched with saturated ammonium chloride solution. The solvents were removed in vacuo and the residue was taken up in ethyl acetate and washed with water. The organic layer was washed with saturated sodium chloride solution and dried over magnesium sulfate. After filtration, evaporation and gravity silica gel chromatography (SGC) with 2% ethyl acetate in petroleum ether as eluant, a mixture of the title compound and methyl 1-(4'-t-butyldimethylsilyloxymethylphenyl)-2-vinylcyclopropane-1-carboxylate (7:1 ratio, total 708 mg) was obtained as an oil. Since the two compounds were inseparable, the mixture was taken on.
