A 50% oil dispersion of sodium hydride (2.11 g., 0.044 mole) in mineral oil is washed with petroleum ether and then suspended in dry dimethylformamide (30 ml.) under a nitrogen atmosphere at room temperature. To this suspension is added a solution of dimethyl-2-methylsulfonyl-azelate (11.8 g., 0.04 mole) in dry dimethylformamide (30 ml.). After the evolution of hydrogen is completed, the mixture is cooled to 5° C. in an ice bath and a solution of 1-iodo-4-acetoxy-5-(3-trifluoromethylphenoxy)pentane (18.3 g., 0.044 mole) in dry dimethylformamide (30 ml.) is added dropwise. After 48 hours, ether is added to the reaction mixture to precipitate sodium iodide which is removed by filtration. The filtrate is concentrated in vacuo to give a residue which is diluted with water, acidified with 6N hydrochloric acid, an extracted with ether. The ether extracts are washed with water until neutral, dried over anhydrous magnesium sulfate, and concentrated in vacuo to give the title compound (20.5 g., 0.035 mole, 88%).
