Triisopropyl borate → 2-Dihydroxyboranyl-9,9-dioctylfluorene

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Reaction Steps

n-BuLi (2.5 M in hexane, 12.0 mL, 30.0 mmol) is slowly added to a solution of 2-bromo-9,9-bis(n-octyl)fluorene (12.0 g, 25.6 mmol) in anhydrous THF (50 mL) at −78° C. At this temperature, the reaction mixture is stirred for 1 h before adding tri-iso-propyl borate (9.0 mL, 7.34 g, 39.0 mmol). The resulting mixture is then warmed to room temperature, stirred overnight followed by quenching with 100 mL HCl (2.0 M), and poured into a large amount of water. After extraction with ethyl ether three times, the organic portions are washed with brine before drying over anhydrous MgSO4. Solid residues collected by evaporating off the solvent are purified by column chromatography on silica gel with petroleum ether/ethyl acetate (2:1) to yield 9,9-bis(n-octyl)fluoren-2-yl-boronic acid (2a) as a white solid (10.0 g, 89%).

Provenance & Evidence