To a degassed solution of Intermediate 11A (3.00 g, 9.99 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-1-carboxylate (4.410 g, 14.99 mmol) and potassium carbonate (4.14 g, 30.0 mmol) in dioxane (20 mL)/water (8 mL) was added Tetrakis (0.577 g, 0.500 mmol). The vial was purged with argon, sealed and stirred at 90° C. for 16 h. Another 20% of tetrakis and boronic ester were added and the reaction mixture was degassed and heated at 90° C. for 24 h. The reaction was cooled down to rt and NaOH (14.99 mL, 14.99 mmol) was added and the reaction was stirred at 50° C. for 5 h. The mixture was partitioned between EtOAc and water. The organic layer was separated. The aqueous phase was extracted with EtOAc, and the combined organic layers were dried over MgSO4 and concentrated in vacuo. The crude material was purified by flash chromatography over 120 g of silica gel (15 min gradient, with 0-100% ethyl acetate in hexanes) to afford Intermediate 11B (2.14 g, 7.45 mmol, 74.5% yield) as a white solid. LCMS=1.86 min [M+1]=288.2 (Method B).
