[C:1]([O:5][C:6]([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[C:14]1[CH:19]=[CH:18][C:17]([CH3:20])=[CH:16][CH:15]=1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[Br:21]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C(Cl)(Cl)(Cl)Cl>[Br:21][CH2:20][C:17]1[CH:18]=[CH:19][C:14]([C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=2[C:6]([O:5][C:1]([CH3:4])([CH3:3])[CH3:2])=[O:7])=[CH:15][CH:16]=1To a solution of 2-t-butoxycarbonyl-4'-methylbiphenyl (25.3 g, 95 mmol) in CCl4 (200 ml) were added freshly opened N-bromosuccinimide <17.6 g, 0.099 mole) and dibenzoyl peroxide (2.28 g, 0.0094 moles). The mixture was refluxed for 4 hours, cooled to room temperature and filtered. The filtrate was washed with sat. NaHSO3 (1×50 ml), sat. NaHCO3 (1×50 ml), water (1×50 ml), sat. NaCl (1×50 ml) and dried over MgSO4. The solution was filtered and concentrated in vacuo. The residue was dissolved in 100 ml of hot hexane. Crystallization gradually took place as the solution cooled. The flask was finally cooled to -20° C. and the precipitate recovered by filtration. The solid was washed with ice cold hexanes and dried in vacuo to give 27 g (88%) of a white solid. 1H-NMR (CDCl3):1.23 (s, 9H), 4.53 (s, 2H), 7.2-7.5 (m, 7H), 7.68 (d, 1H).
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