[CH:1]1([N:7]2[CH2:11][CH2:10][CH:9]([CH2:12][C:13]3[C:18]([Cl:19])=[CH:17][C:16]([O:20]C)=[CH:15][C:14]=3[Cl:22])[C:8]2=[O:23])[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1.B(Br)(Br)Br.C(=O)(O)[O-].[Na+]>ClCCl>[CH:1]1([N:7]2[CH2:11][CH2:10][CH:9]([CH2:12][C:13]3[C:18]([Cl:19])=[CH:17][C:16]([OH:20])=[CH:15][C:14]=3[Cl:22])[C:8]2=[O:23])[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6]1Dissolve 1-cyclohexyl-3-(2,6-dichloro-4-methoxy-benzyl)-pyrrolidin-2-one (86 g, 241.4 mmol) in 1300 mL dichloromethane then cool to 0° C. under nitrogen. Slowly add BBr3 (120.9 g, 482.75 mmol) to the stirring cold solution keeping the internal temperature below 3.5° C. Stir the solution cold for ˜2 hours, then pour into 4 L of saturated sodium bicarbonate and stir rapidly for ˜20 minutes. Filter and wash the solid with water, then air dry on the funnel. Separate the organic portion of the filtrate and wash with water then brine. Dry over sodium sulfate, filter and concentrate under vacuum. Suspend the resultant tan solid in dichloromethane, filter, wash the solid with dichloromethane and dry to yield 10.5 g of off-white solid. Combine all solids and dry over night in a vacuum oven at 45° C. to yield 78.6 g (95%) of a light-tan solid: MS: (m/z) 342 (M+).
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