10.00 g (32.36 mmol) of 1-bromo-4-(trans-4-pentylcyclohexyl)benzene, 3.89 g (35.60 mmol) of trimethylsilylacetylene, 0.45 g (0.65 mmol) of bis(triphenylphosphine)palladium(II) chloride and 0.062 g (0.32 mmol) of copper(I) iodide are heated for 6 hours at the reflux temperature in 100 ml of diisopropylamine. The solvent is subsequently stripped off, and the soluble constituents of the residue are chromatographed on silica gel using n-hexane, giving 7.32 g of 1-(trimethylsilylethynyl)-4-(trans-4-pentylcyclohexyl)benzene, ##STR5## which is stirred for 1 hour at room temperature in 220 ml of methanol with 1.38 g (24.70 mmol) of potassium hydroxide. Work-up by evaporation of the solvent, partitioning between ether and water, drying and evaporation of the organic phase gives 4.95 g of 1-ethynyl-4-(trans-4-pentylcyclohexyl)benzene. ##STR6##
