6-bromo-3-iodo-9-((2-(trimethylsilyl)ethoxy)methyl)-9H-dipyrido[2,3-b;4',3'-d]pyrrole → 6-Bromo-9-((2-(trimethylsilyl)ethoxy)methyl)-9H-dipyrido[2,3-b;4',3'-d]pyrrole

A solution of 6-bromo-3-iodo-9-((2-(trimethylsilyl)ethoxy)methyl)-9H-dipyrido[2,3-b;4′,3′-d]pyrrole (3.0 g, 5.95 mmol) in tetrahydrofuran (40 mL) was cooled at −78° C. To this was added isopropylmagnesium chloride (2.0N solution in tetrahydrofuran, 3.12 mL, 6.2 mmol) dropwise over five minutes. The reaction mixture was stirred at this temperature for 1.5 hours and then quenched with saturated aqueous ammonium chloride solution (1 mL). The reaction mixture was then diluted with 25 mL water and extracted with ethyl acetate (150 mL). The organic layer was separated, washed with water (50 mL) then brine (50 mL), dried over sodium sulfate, filtered, and the concentrated in vacuo to afford a yellow oil, which was used in the next step without any further purification (2.2 g, 100%).