An oven-dried resealable Schlenk tube was charged with 6′-bromospiro[cyclopentane-1,3′-indolin]-2′-one (preparation 2, 0.650 g, 2.44 mmol), 4-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoic acid (WO200700565, 0.96 g, 3.66 mmol), 1,4-dioxane (25 mL) and a 2M aqueous cesium carbonate solution (3.7 mL, 7.4 mmol). The Schlenk tube was subjected to three cycles of evacuation-backfilling with argon, and 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride dichloromethane complex (0.12 g, 0.15 mmol) was added. After three further cycles of evacuation-backfilling with argon, the Schlenk tube was sealed and the mixture was stirred and heated in an oil bath to 100-110° C. After 20 hours, the mixture was cooled and partitioned between water and ethyl acetate. The combined organic extract was dried (MgSO4) and evaporated in vacuo. Purification of the residue by flash chromatography (95:5 dichloromethane/methanol) gave the title compound (0.64 g, 81%) as a yellow solid.
