1,3,2-Dioxaborolane, 2,2'-(9,9-dimethyl-9H-fluorene-2,7-diyl)bis[4,4,5,5-tetramethyl]

28320-32-3

73183-34-3

325129-69-9

General procedure for the synthesis of 9,9-dimethylfluorene-2,7-diboronic acid pinacol ester from 2,7-dibromo-9,9-dimethylfluorene and pinacol ester of bis(pinacolato): 2,7-dibromo-9,9-dimethyl-9H-fluorene (130 g, 369 mmol), bis(pinacolato)diborane (225 g, 886 mmol), and potassium acetate (217 g, 2.22 mol ) were suspended in 1.4 L of dioxane. The mixed solution was degassed and saturated with argon. PdCl2(dppf)CH2Cl2 (15 g, 18 mmol) was subsequently added. The reaction mixture was heated to reflux and kept for 4 hours under the protection of inert atmosphere. After completion of the reaction, the mixture was filtered and the filtrate was washed with dioxane. The crude product was subjected to Soxhlet extraction using THF as a solvent to extract the residue, after which it was filtered again. A final 137 g of gray solid product was obtained in 83% of the theoretical yield. The purity of the product was confirmed by NMR (CDCl3 as solvent) and was greater than 95%. The following compounds were prepared using similar methods: