A 100 mL reaction flask was charged with tert-butyl 4,4′-bipiperidine-1-carboxylate (1.14 g; 4.25 mmol), methyl 4-bromobenzoate (913 mg; 4.25 mmol), cesium carbonate (4.15 g; 12.74 mmol), Pd(OAc)2 (48 mg; 0.212 mmol) and 2-(diphenylphosphino)-2′-(N—N-dimethylamino)biphenyl (162 mg; 0.425 mmol). NMP (outgassed by bubbling with nitrogen for 10 min; 10 mL) was added and the mixture stirred at 90° C. for 18 hr. The mixture was diluted with dichloromethane (100 mL) and filtered through Celite. The filtrate was washed with water (4×25 mL). The organic was dried over magnesium sulfate, filtered and evaporated to a solid. The solid was digested at reflux (MTBE). After cooling, the white solid was recovered by filtration. The filtrate was evaporated and chromatographed (Horizon; 0% to 100% EtOAc/hex; linear gradient). The fractions containing the desired compound were recovered and combined with the solid to give the title compound.
