[1,1′-bis(diphenylphosphino)ferrocene]-dichloropalladium(II) complex with dichloromethane (1:1) (18 mg, 0.022 mmol) was added to a mixture of tert-butyl 4-(3-chloro-2-fluorobenzoyl)-3-((pyridin-3-yloxy)methyl)piperazine-1-carboxylate (100 mg, 0.222 mmol), benzeneboronic acid (81 mg, 0.67 mmol) and sodium carbonate (71 mg, 0.67 mmol) in toluene (4 mL), 1,4-dioxane (1 mL), and water (1 mL). The reaction mixture was heated to 110° C. overnight. Additional portions of the palladium catalyst, boronic acid and sodium carbonate were added and heating continued at 110° C. After stirring overnight, additional portions of the palladium catalyst, boronic acid and sodium carbonate were again added and heating continued at 110° C. overnight. Upon cooling to room temperature, the reaction mixture was filtered through Celite®, concentrated under reduced pressure, and purified by HPLC (10 to 90% MeCN/0.1% TFA in H2O/0.1% TFA gradient). This gave 115 mg (86%) of the title compound as the TFA salt that was ˜80% pure by LC-MS. LC-MS: RT=9.06 min, [M+H]+=492.9. 26.3 mg (22%) of tert-butyl 4-(2-fluorobenzoyl)-3-((pyridin-3-yloxy)methyl)piperazine-1-carboxylate were also isolated as the TFA salt. LC-MS: RT=7.53 min, [M+H]+=416.7.
