Add n-butyllithium (2.5 N, 1.44 mL) to the solution of 1,3-dibromo-5-(trifluoromethyl)benzene (1 g, 3.28 mmol) in THF (15 mL) at −78° C. and stir the mixture at −78° C. for 1 hr. Then add tert-butyl 4-(methoxy(methyl)carbamoyl) piperidine-1-carboxylate (1.4 g, 4.92 mmol) obtained in Step 1 to the mixture and continue stirring. TLC (PE:EtOAc=5:1) shows the reaction is complete. Quench the reaction mixture with saturated ammonium chloride solution. Partition between EtOAc and water, separate the organic layer, and wash with brine, dry over anhydrous sodium sulfate, concentrate to give the crude product. Purify by flash chromatography (silica gel, DCM:MeOH=20:1) to afford the product (387 mg, 27%). MS: (M+1): 436.
