tert-Butyl 4-(4-chloropyrimidin-2-yl)piperazine-1-carboxylate (300 mg, 1.0 mmol) and phenylboronic acid (183 mg, 1.5 mmol) were dissolved in toluene (10 mL) and the solution was purged with argon for 10 min. Potassium phosphate (426 mg, 2.0 mmol) was added to the reaction mixture, followed by a catalytic amount of Pd2(dba)3 (9 mg, 0.01 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (23 mg, 0.04 mmol). The reaction mixture was then heated to 115° C. for 10 h, cooled to room temperature, diluted with EtOAc, and filtered through Celite. The organic layer was washed with water and brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude product was purified by column chromatography (silica 60-120 mesh, eluent 30% EtOAc in petroleum ether) to get tert-butyl 4-(4-phenylpyrimidin-2-yl)piperazine-1-carboxylate (250 mg, yield 73%). 1H NMR (300 MHz, MeOD) δ 8.28-8.23 (m, 3H), 7.46-7.43 (m, 3H), 7.34 (m, 1H), 3.80-3.77 (m, 4H), 3.56-3.53 (m, 4H), 1.48 (s, 9H). MS (ESI) m/z: Calculated for C19H24N4O2: 340.19. found: 341.2 (M+H)+
