1.61 ml (751 mg, 5.6 mmol) of 3.6N ethylmagnesium bromide in ether was added dropwise, under argon to a solution of 1.34 g (6 mmol) of 9-(m-methylphenoxy)-1,4,7-nonatriyne in 20 ml of anhydrous tetrahydrofuran. The temperature was maintained at 0° C. The reaction mixture was stirred for one hour further at 0° C., then allowed to warm to room temperature, and then 50 mg of cuprous cyanide wasadded. The mixture was stirred for 20 minutes, heated to 40° C. and then 1 g (3.75 mmol) of 7-iodo-5-heptynoic acid methyl ester was added. The resulting mixture was stirred during 4 hours at 40° C. The reaction mixture was then poured into 60 ml of 1N sulfuric acid and ice and the product extracted with ether (3×100 ml). The combined organic extract was concentrated to about 1/5 its original volume and washed several times with EDTA and water, dried over sodium sulfate and evaporated in vacuo. The crude material was purified by column chromatography on 75 g of silica gel, using hexane:ethyl acetate (85:15) as eluant, to obtain 16-(m-methylphenoxy)hexadeca-5,8,11,14-tetraynoic acid methyl ester, as an oil. The product was stored in dry ice.
