4,4,5,5-tetramethyl-2-(9,9'-spirobi[9H-fluoren]-4-yl)-1,3,2-Dioxaborolane

1161009-88-6

73183-34-3

1161009-89-7

General procedure for the synthesis of 2-(9,9'-spirobi[fluoren]-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolanes from 4-bromo-9,9'-spirobi(fluorene) and bipinacolate: 1. 60 g (152 mmol) of 4-bromo-9,9'-spirobifluorene, 47.2 g (182.1 mmol) of pinacol ester of bisboronic acid, 3.72 g (4.55 mmol) of 1,1'-bis(diphenylphosphino)-ferrocene-palladium(II) dichloromethane complex and 44.7 g (455 mmol) of potassium acetate were dissolved in 600 ml of toluene. 2. The reaction mixture was heated under reflux conditions for 16 hours. 3. After completion of the reaction, cool to room temperature, add 200 ml of water and continue stirring for 30 minutes. 4. Separate the organic phase and filter through a short diatomaceous earth bed. 5. The solvent was removed by pressure reducing distillation. 6. The residue was purified by multiple recrystallization through a heptane/toluene solvent mixture. 7. 67.1 g of product was obtained in 96% yield.