Into a 20 mL sealed tube was placed 2-chloro-3-(trifluoromethyl)pyridine (500 mg, 2.76 mmol, 1.00 equiv), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (1.705 g, 5.52 mmol, 2.00 equiv), PCy3 (216.4 mg, 0.77 mmol, 0.28 equiv), Pd2(dba)3 (304.7 mg, 0.33 mmol, 0.12 equiv), NaOt-Bu (828 mg, 8.28 mmol, 3.00 equiv), dioxane (8 mL). The resulting solution was stirred overnight at 100° C. in an oil bath. The resulting mixture was concentrated under vacuum. The residue was applied onto a silica gel column with PE/EA (10:1). This resulted in 449.3 mg (46%) of tert-butyl 4-(3-(trifluoromethyl)pyridin-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate as yellow oil.
