Cesium carbonate (672 mg, 2.063 mmol), BINAP (64.2 mg, 0.103 mmol), 1-(oxetan-3-yl)piperazine (176 mg, 1.238 mmol) and Pd2(dba)3 (94 mg, 0.103 mmol) were weighed into a 25 mL round bottom flask at room temperature. A solution of tert-butyl (3-bromo-2-chloro-5-(difluoromethyl)phenyl)(4-methoxybenzyl)carbamate in toluene (4294 μl, 1.031 mmol) was added and the reaction was degassed 3 times by evacuating the flask under vacuum and then purging with N2. The reaction mixture was heated to 106° C. for 16 h and then cooled to room temperature. The reaction mixture was diluted with EtOAc, sonicated, filtered through celite and concentrated. The product was purified by column chromatography (40 g SiO2, 30 to 100% EtOAc-hexane gradient elution) to afford 312 mg of tert-butyl (2-chloro-5-(difluoromethyl)-3-(4-(oxetan-3-yl)piperazin-1-yl)phenyl)(4-methoxybenzyl)carbamate.
