Triphenylphosphine → (1S,4R)-4-(4,7-difluoro-1H-imidazo[4,5-c]pyridin-1-yl)cyclopent-2-enol

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4,7-difluoro-1H-imidazo[4,5-c]pyridine (1-4) (2.0 g, 12.9 mmol, 1 equiv) was dissolved in dry DMF (21 mL). Sodium hydride (542 mg, 13.5 mmol, 1.05 equiv) was carefully added. The resulting mixture was stirred at ambient temperature for 45 minutes at which point triphenylphosphine (507 mg, 1.9 mmol, 0.15 equiv), Pd-tetrakis (745 mg, 0.6 mmol, 0.05 equiv) and (1R,3S)-(+)-cis-4-cyclopentene-1,3-diol 1-acetate (3-1) (2.2 g, 15.5 mmol, 1.2 equiv) in dry THF (21 mL) were added. The mixture was stirred at 60° C. for 16 hours, then cooled to ambient temperature, diluted with 100 mL EtOAc and washed with 50 mL water. The aqueous layer was washed with EtOAc three additional times, and the combined washings were dried over MgSO4, filtered and concentrated. The crude residue was purified by reverse phase chromatography (5-95% CH3CN/water with 0.1% TFA modifier) to afford (1S,4R)-4-(4,7-difluoro-1H-imidazo[4,5-c]pyridin-1-yl)cyclopent-2-enol (3-2) as a white solid. LRMS m/z (M+H) 238.0 found, 238.1 required.

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