Under nitrogen protection, 2-bromo-9,9-dimethylfluorene (100 g, 366 mmol, purchased from Sigma Aldrich Co., Ltd.) was dissolved in dimethylformamide (DMF, 1.1 L). Subsequently, bis(pinacolato)diboron (112 g, 439 mmol), [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (2.99 g, 3.66 mmol) and potassium acetate (108 g, 1,098 mmol) were added to the solution. The reaction mixture was heated to 150 °C and refluxed for 5 hours. After completion of the reaction, water was added to the reaction solution, the mixture was filtered and dried in a vacuum oven. The resulting residue was separated and purified by fast column chromatography to afford the target product fluorene-2-boronic acid katanol ester (102 g, 87% yield). High resolution mass spectrometry (HRMS, 70 eV, EI+): m/z calculated value of C21H25BO2[M]+ was 320.1948, measured value was 320. elemental analysis results: C, 79%; H, 8%.
