A mixture of 4-methylene-piperidine-1-carboxylic acid tert-butyl ester (0.70 g, 3.55 mmol) and 9-borabicyclo[3,3,1]nonane (0.5M solution in THF, 7 mL, 3.5 mmol) were heated at reflux for 1.5 h. The reaction mixture was cooled and added to a degassed mixture of 9-benzenesulfonyl-5-bromo-9H-dipyrido[2,3-b;4′,3′-d]pyrrole-6-carbonitrile (0.41 g, 1.0 mmol), [1,1-bis(diphenylphosphino) ferrocene]dichloropalladium(II) (0.090 g, 0.11 mmol) and potassium carbonate (0.18 g, 1.3 mmol) in water (1 mL) and DMF (10 mL) and the reaction mixture was then heated at 65° C. for 1.25 h. After cooling to ambient temperature the reaction mixture was then diluted with water (5 mL) and dichloromethane (10 mL). The aqueous phase was extracted with dichloromethane (2×15 mL) and the combined organic phase was washed with brine (15 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was triturated with pentane (10 mL) and the resultant material was purified by flash chromatography (silica, 5 g column, SPE-Si II, 0-2% methanol in DCM) to afford title compound as a yellow solid (202 mg, 38%). 1H NMR (CDCl3, 400 MHz): 9.81 (s, 1H), 8.79 (dd, J=4.8, 1.6 Hz, 1H), 8.33-8.27 (m, 3H), 7.66-7.60 (m, 1H), 7.55-7.46 (m, 3H), 4.22-4.01 (m, 2H), 3.34-3.27 (m, 2H), 2.62-2.50 (m, 2H), 1.97-1.76 (m, 2H), 1.72-1.46 (m, 3H), 1.45 (s, 9H).
