CC(C)CC(C1C=CC(C)=CC=1)=O.[Br:14][CH2:15][C:16]1(CBr)[CH:21]=[CH:20][C:19]([C:22](=[O:27])[CH2:23][CH:24]([CH3:26])[CH3:25])=[CH:18][CH2:17]1>>[Br:14][CH2:15][C:16]1[CH:21]=[CH:20][C:19]([C:22](=[O:27])[CH2:23][CH:24]([CH3:25])[CH3:26])=[CH:18][CH:17]=1Add NBS (1.6 g, 9.2 mmol) to a solution of 3-methyl-1-p-tolyl-butan-1-one (1.5 g, 8.4 mmol) and AIBN (1.4 g, 8.4 mmol) in carbon tetrachloride (30 mL) and heat to reflux for 18 h. Cool the reaction mixture to room temperature and pour into water (500 mL). Extract with EtOAc (3×100 mL), wash the combined organic extracts with brine (300 mL), dry over Na2SO4 and concentrate in vacuo to obtain 2.9 g of a brown oil, consisting of the desired intermediate with a small amount of unreacted 3-methyl-1-p-tolyl-butan-1-one and 1-(4,4-dibromomethyl-phenyl)-3-methyl-butan-1-one. Use this mixture in the next step without additional purification. MS (APCI+) m/z: 255 (M+).
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