To a solution of 1-benzenesulfonyl-5-chloro-3-iodo-1H-pyrrolo[2,3-b]pyridine (581, 4.40 g, 10.5 mmol) in tetrahydrofuran (30.0 mL) at −45° C. under nitrogen, a solution of isopropylmagnesium chloride (2.0 M in tetrahydrofuran, 5.4 mL) was added slowly over 10 minutes. The reaction was allowed to warm to −25° C. over 30 minutes. The reaction was cooled to −65° C., followed by adding the cold deprotonated (4-chloro-5-formyl-thiazol-2-yl)-carbamic acid tert-butyl ester 589, which was prepared in situ by adding isopropylmagnesium chloride (2.0 M in tetrahydrofuran, 5.0 mL) to (4-chloro-5-formyl-thiazol-2-yl)-carbamic acid tert-butyl ester (589, 2.51 g, 9.55 mmol) in tetrahydrofuran (23.0 mL) at −78° C. under an atmosphere of nitrogen. The reaction was allowed to warm to room temperature in 2 hours, then poured into aqueous ammonium chloride, and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated and purified by silica gel column chromatography eluting with 25% to 100% ethyl acetate in hexane to give the desired compound (590, 3.70 g, 60.3%). MS (ESI) [M+H+]+=554.2.
