N-Fluorobenzenesulfonimide → 5-Fluoro-1-[tri(propan-2-yl)silyl]-1H-pyrrolo[2,3-b]pyridine

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Reaction Conditions

Reaction Steps

2.5M Butyl lithium (4.4 mL, 10.8 mmol) was added dropwise to a stirred solution of 5-bromo-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine (2.55 g, 7.23 mmol) in THF (65 mL) over 10 min at −78° C. under nitrogen in three necked flask. The resulting solution was stirred at −78° C. for 1 h and solid N-fluorobenzenesulfonimide (2.84 g, 9.03 mmol) was added in one portion and stirred at −78° C. for 2 h. The solvent was evaporated and the crude material was dissolved in water (50 mL) and extracted with EtOAc (3×25 mL). The organic extract was dried and concentrated under reduced pressure to give a residue which was suspended in hexane (5 mL) and filtered. The filtrate was chromatographed (Biotage HPFC) on silica gel eluting with hexane to give 5-fluoro-1-(triisopropylsilyl)-1H-pyrrolo[2,3-b]pyridine (1.06 g, 50.2%) as a viscous oil.; Mass Spec.; MS 293 (M+1); 1H NMR(CDCl3,500 MHz) 8.11(d,1H), 7.51(dd,1H), 7.34(d,1H), 6.50(d,1H), 1.84(q,3H), 1.10(d,18H).

Provenance & Evidence