[CH3:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([CH3:8])[C:3]=1[B:9]1[O:13][C:12]([CH3:15])([CH3:14])[C:11]([CH3:17])([CH3:16])[O:10]1.[Br:18]N1C(=O)CCC1=O.CC(N=NC(C#N)(C)C)(C#N)C>C(#N)C>[Br:18][CH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([CH3:8])[C:3]=1[B:9]1[O:10][C:11]([CH3:17])([CH3:16])[C:12]([CH3:15])([CH3:14])[O:13]1A mixture of 43.0 g (185 mmol) of 2-(2,6-dimethylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 42.9 g (241 mmol) of N-bromosuccinimide, and 0.40 g (3.27 mmol) of AIBN in 1000 ml of acetonitrile was refluxed for 2 h. Then, this mixture was cooled to room temperature and evaporated to dryness. The residue was dissolved in 500 ml of hexane. The precipitate was filtered on glass frit (G3), and the filtrate was evaporated to dryness to give yellowish crystalline solid. Yield 37.9 g (66%). Anal. calc. for C14H20BBrO2: C, 54.06; H, 6.48. Found: C, 54.35; H, 6.72. 1H NMR (CDCl3): δ 7.21 (m, 1H, 4-H), 7.15 (m, 1H, 3-H), 7.07 (m, 1H, 5-H), 4.72 (s, 2H, CH2Br), 2.44 (s, 3H, 6-Me), 1.42 (s, 12H, Bpin).
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