CC1(C)CCCC(C)(C)N1.[Li+].CCC[CH2-].[CH:16]([Si:19]([CH:34]([CH3:36])[CH3:35])([CH:31]([CH3:33])[CH3:32])[N:20]1[C:24]2[N:25]=[CH:26][CH:27]=[C:28]([C:29]#[N:30])[C:23]=2[CH:22]=[CH:21]1)([CH3:18])[CH3:17].C(Br)(Br)(Br)[Br:38]>O1CCCC1>[Br:38][C:27]1[CH:26]=[N:25][C:24]2[N:20]([Si:19]([CH:16]([CH3:18])[CH3:17])([CH:31]([CH3:33])[CH3:32])[CH:34]([CH3:36])[CH3:35])[CH:21]=[CH:22][C:23]=2[C:28]=1[C:29]#[N:30]
2,2,6,6-Tetramethylpiperidine (380 μL, 2.25 mol) was dissolved in tetrahydrofuran (3 mL) and cooled to 0° C. N-Butyllithium (2.5 M in hexanes, 1.06 mL, 2.66 mmol) was added dropwise and the mixture was stirred at 0° C. for 10 min, then cooled to −78° C. A solution of 1-triisopropylsilanyl-1H-pyrrolo[2,3-b]pyridine-4-carbonitrile (613 mg, 2.04 mmol) in tetrahydrofuran (2 mL) was added at −78° C. and the mixture was stirred at −78° C. for 1 h. A solution of carbontetrabromide (2 g, 6.1 mmol) in tetrahydrofuran (5 mL) was added quickly at −78° C. and the mixture was stirred for 15 min. The reaction was quenched with saturated ammonium chloride solution. The mixture was warmed to ambient temperature and applied to a Varian chemelut cartridge and eluted with ethyl acetate. The crude product was purified by flash silica gel chromatography using a gradient of dichloromethane in hexanes to afford 5-Bromo-1-triisopropylsilanyl-1H-pyrrolo[2,3-b]pyridine-4-carbonitrile (160 mg, 0.42 mmol, 21% yield). 1H NMR (500 MHz, DMSO-d6) δ 8.57 (s, 1H), 7.88 (d, J=3.5 Hz, 1H), 6.83 (d, J=3.5 Hz, 1H), 1.85 (septet, J=7.5 Hz, 3H), 1.04 (d, J=7.5 Hz, 18H). MS: m/z 378.0/380.0 (M+H+).
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