To a solution of 2-bromofluorene (2.5 g, 10 mmol) in toluene (40 ml) was added tetrabutylammonium bromide (0.8 g, 2.48 mmol) as a phase transfer catalyst. Freshly prepared aqueous sodium hydroxide solution (25 ml, 50% w/w) was added to the reaction system at once. The reaction mixture immediately turned orange and gradually became viscous. Subsequently, ethyl iodide (2.4 ml, 30 mmol) was slowly added to the reaction system. The reaction mixture was stirred continuously at 60 °C for 8 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (25 ml) and washed several times with deionized water. The organic layer was separated and dried with anhydrous magnesium sulfate and subsequently concentrated under vacuum to give the crude product. The crude product was purified by column chromatography (silica gel as stationary phase, hexane as eluent, Rf=0.8 for thin layer chromatographic detection), and the final product was obtained as 2-bromo-9,9-diethylfluorene as a colorless oil (2.5 g) in 82% yield.1H NMR (CDCl3) δ: 0.24 (t, J=8Hz, 6H), 1.94-1.91 (m, 4H), 7.25- 7.23 (m, 3H), 7.38-7.36 (m, 2H), 7.49-7.46 (m, 1H), 7.61-7.59 (m, 1H).
