1,1'-Biphenyl-4-yl-boronic acid → 2,2',4,4',7,7'-Hexabiphenylyl-9,9'-spirobifluorene

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Reaction Steps

1.6 g of hexabromospirobifluorene and 3 g of biphenylboronic acid were suspended in a mixture of 50 ml of toluene and 50 ml of 1 M potassium carbonate solution in a 250 ml two-necked flask with a reflux condenser and precision glass stirrer. The mixture was boiled under reflux under nitrogen, and 115 mg of tetrakis(triphenylphosphine)palladium in 5 ml of toluene were added. The mixture was boiled under reflux for 7 hours, while stirring. When the reaction had ended, the cooled solution was filtered off and the filtrate was extracted 2× by shaking with water (chloroform was added for better phase separation). The organic phase was dried over sodium sulfate and filtered over a short column with silica gel and the solvent was then stripped off on a rotary evaporator. For further purification, the product was recrystallized from methylene chloride/pentane. 2 g (80%) of colorless crystals which fluoresce blue under UV illumination were obtained.

Provenance & Evidence