4,4"-Bis(2,3,4,5-tetramethylcyclopentadienyl)terphenyl (3a). In a dry Schlenk tube under nitrogen, a solution of t-BuLi (22 mL, 37.12 mmol) was added dropwise to a slurry of 4,4"dibromoterphenyl (3.6 g, 9.28 mmol) in diethyl ether (75 mL) at -78°C. The reaction mixture was stirred for 4 h at this temperature and then 1 h at room temperature. It was again cooled to -78°C and a solution of 2,3,4,5-tetramethyl-cyclopent-2-enone (2.56 g, 18.56 mmol) in THF (60 mL) was added dropwise. The reaction

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... xture was stirred for two days at room temperature. A saturated solution of NH 4 Cl was added to quench the reaction and both layers were separated. The aqueous phase was further extracted with diethyl ether and the combined organic phases were dried over MgSO 4. The solvent was evaporated and the colourless oil was redissolved in dichloromethane (30 mL). A catalytic amount of p-toluenesulfonic acid was added to the reaction mixture changing the color of the solution to yellow. After stirring at room temperature for 30 min, most of the solvent was evaporated and a small amount of petroleum ether was added to precipitate out the product. After filtration and washing of the precipitates with diethyl ether and petroleum ether, the required product was obtained as a yellow powder. (Yield 43%).