GENERAL PROCEDURE: 9-(2-Biphenylyl)-9-fluorenol (130 mg, 0.5 mmol) was placed in a 5 mL round-bottomed flask and 1 mL of dry nitromethane was added as solvent. Anhydrous FeCl3 (5 mg, 0.025 mmol) was then added and the reaction mixture was stirred at room temperature for 5 min. Upon completion of the reaction, the solvent was removed by vacuum evaporation and the residue was purified by silica gel column chromatography using petroleum ether (boiling point 60-80 °C) as eluent to afford the target product 9,9-spirobifluorene (116 mg, 0.48 mmol, 96% yield) as a white solid with a melting point of 132 °C. 1H NMR (CDCl3, 300 MHz) δ 5.08 (s , 1H), 7.11-7.12 (m, 2H), 7.25-7.36 (m, 7H), 7.42 (t, J = 7.29 Hz, 2H), 7.84 (d, J = 7.6 Hz, 2H) ppm.13C NMR (CDCl3, 75 MHz) δ 54.4, 119.8, 125.3, 126.8, 127.3, 128.3, 128.7, 141.0, 141.6, 147.8 ppm.
![9,9'-Spirobi[9H-fluorene]](/CAS/GIF/159-66-0.gif)