The general procedure for the synthesis of 1,2,3,6-tetrahydro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine from tert-butyl 4-(((trifluoromethyl)sulfonyl)oxy)-5,6-dihydropyridine-1(2H)-carboxylate and bipinacolato pinacol ester was carried out as follows: to a dry reaction flask, bis(pinacolato)diboron ( 3.37 g, 13.28 mmol), potassium acetate (KOAc, 3.58 g, 36.46 mmol), [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (PDCL2DPPF, 0.27 g, 0.36 mmol), and 1,1'-bis(diphenylphosphino)ferrocene (dppf, 0.2 g, 0.36 mmol) to a dry reaction flask, and the reaction system was subsequently flushed with argon to flush the reaction system. A solution of tert-butyl 4-(((trifluoromethyl)sulfonyl)oxy)-5,6-dihydropyridine-1(2H)-carboxylate (4.00 g, 12.07 mmol) in dioxane (35 mL) was added, and the reaction mixture was stirred at 80 °C overnight. After completion of the reaction, it was cooled to room temperature, diluted with water (50 mL) and extracted with ethyl acetate (EtOAc, 50 mL). The organic layer was separated, washed with saturated saline (50 mL), dried over anhydrous magnesium sulfate (MgSO4) and filtered. The filtrate was concentrated under reduced pressure and the crude product was purified by fast column chromatography (eluent ratio of 9:1 hexane:ethyl acetate) to give the target product as a white solid (4.5 g, 100% yield).
