A mixture of 2-bromo-7-pentyloxyfluorene (12 g), trimethylsilylacetylene (7.1 g), dichlorobis(triphenylphosphine)palladium (0.3 g), copper iodide (0.08 g), triphenylphosphine (0.2 g) and triethylamine (200 mL) was heated for 3 hours while refluxing. Insoluble matters were removed from the reaction mixture by filtration, and triethylamine was distilled off under reduced pressure. The residue was purified by means of column chromatography (silica gel, eluting solvent: toluene) to obtain 6.5 g of 2-pentyloxy-7-trimethylsilylethynylfluorene. This was dissolved in tetrahydrofuran (100 mL) and cooled down to −60° C. on a dry ice-acetone bath. A 1M solution (46 mL) of tetraethylammonium fluoride was added thereto, and then the dry ice-acetone bath was removed, followed by stirring the solution until the temperature came up to −10° C. At a point of time when −10° C. was reached, water (30 mL) was added and stirred until the temperature came up to a room temperature, and then water was further added to terminate the reaction. The product was extracted with toluene, and the toluene layer was dried on anhydrous magnesium sulfate. A residue obtained by distilling the solvent off was purified by means of column chromatography (silica gel, eluting solvent: toluene). Then, it was recrystallized from ethanol to obtain 2-pentyloxy-7-ethynylfluorene (5 g) of colorless needle crystal. The melting point of this compound was 108° C.
