General procedure for the synthesis of 2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane from 4-bromodibenzo[b,d]furan and pinacol bis(boronic acid) ester: 4-bromodibenzo[b,d]furan (10.0 g, 38.1 mmol) was dissolved in 300 mL of tetrahydrofuran, followed by the reaction of 4-bromodibenzofuran (1.3 g, 1.9 mmol) in a room temperature. Bis(triphenylphosphine)palladium(II) dichloride (1.3 g, 1.9 mmol) was added and the reaction mixture was stirred for about 5 minutes. Next, bis(pinacolato)diboron (14.5 g, 57.2 mmol) and potassium acetate (11.2 g, 114.3 mmol) were added to the reaction system and the mixture was heated at reflux at 80 °C for 24 hours. Upon completion of the reaction, the reaction solution was transferred to 200 mL of ethyl acetate for extraction and the organic layer was concentrated by distillation under reduced pressure and dried with anhydrous magnesium sulfate. The resulting crude product was purified by column chromatography to afford the target compound 2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (ca. 10.0 g, 34.3 mmol, 90% yield). The structure of the resulting compound was confirmed by LC-MS.
![2-(dibenzo[b,d]furan-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane](/CAS/20150408/GIF/912824-85-2.gif)