[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[Br:11][C:12]1[CH:13]=[CH:14][C:15]([C:18]2[O:22][CH:21]=[N:20][C:19]=2[CH2:23][CH3:24])=[N:16][CH:17]=1.[Cl:25]C(Cl)(Cl)C(Cl)(Cl)Cl>C1COCC1.O>[Br:11][C:12]1[CH:13]=[CH:14][C:15]([C:18]2[O:22][C:21]([Cl:25])=[N:20][C:19]=2[CH2:23][CH3:24])=[N:16][CH:17]=1LiHMDS (1.0 M in THF, 8.5 mL, 8.5 mmol) was added dropwise to a solution of Example 44A (1.97 g, 7.78 mmol) in THF (26 mL) at −78° C. After 30 min solid hexachloroethane (1.84 g, 7.78 mmol) was added in one portion and the reaction mixture was stirred while warming to ambient temperature overnight. The reaction was diluted with water and extracted with EtOAc. The organic extract was washed with water and brine, dried over Na2SO4, filtered, and concentrated in vacuo. Chromatography on silica gel (Analogix® Intelliflash 280™; SF25-120 g column; 100% hexane 0-5 min, then 0% to 25% EtOAc/hexanes eluant, 5-40 min) afforded 1.99 g (89%) of the title compound as a yellow oil that solidified on standing. 1H NMR (300 MHz, CDCl3) δ 8.67 (dd, J=2.4, 0.6, 1H), 7.86 (dd, J=8.5, 2.4, 1H), 7.47 (dd, J=8.5, 0.6, 1H), 3.02 (q, J=7.5, 2H), 1.27 (t, J=7.5, 3H). MS (DCI+) m/z 287/289 (M+H).
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