To a nitrogen gas purged sealable vial of 5-bromo-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-pyrrolo[2,3-b]pyridine 4-1a (3000 mg, 9.17 mmol), copper(i) iodide (6983 mg, 36.7 mmol) and sodium 3-methoxy-3-oxopropane-1-sulfinate (TYGER) (6385 mg, 36.7 mmol) was added DMSO (15 ml). The reaction mixture was heated in an oil bath at 105° C. for 18 hrs. LCMS analysis showed reaction to be a mixture of desired ester and acid. The reaction was quenched into ethyl acetate (200 ml) and water (200 ml) and the ph adjusted from 7 to 3 with 1N HCl. The reaction was filtered thru celite and sand and the filtrate layers separated. The organic which contained a mix of acid and ester was dried over sodium sulfate, filtered and concentrated to an oil. The oil was azeotroped with toluene to remove any remaining water to give a brown oil, 3.4 gms. The oil was dissolved in dichloromethane (20 ml) and methanol (20.00 ml) cooled to 0° C. and TMS-Diazomethane (4.94 ml, 9.88 mmol) slowly added dropwise. The reaction was stirred at 0° C. for 10 minutes, quenched with aq. KHSO4 and allowed to stir at room temperature for 1 hr. The reaction was concentrated to remove methanol and the product extracted into ethyl acetate (100 ml), dried over sodium sulfate and concentrated to oil. The oil was chromatographed on silica (100 g, 0-50% ethyl acetate/hexanes) to give the product 4-1b as oil, 1.46 g.
