tert-Butyl[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin -2-yl]carbamate

207799-10-8

73183-34-3

1095708-32-9

A reaction mixture was prepared in dimethyl sulfoxide (8 mL) with 2-Boc amine-4-bromopyridine (0.494 g, 1.81 mmol), pinacol ester of bisboronic acid (1.4 g, 5.51 mmol) and potassium acetate (0.535 g, 5.45 mmol). The mixture was purged with nitrogen for 10 min to deoxygenate. Subsequently, [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (0.150 g, 0.184 mmol) was added and again purged with nitrogen for 5 min. Under nitrogen protection, the reaction mixture was heated to 85 °C and stirred for 1 hour. Upon completion of the reaction, the mixture was diluted with ethyl acetate (15 mL) and washed with 0.2 M aqueous hydrochloric acid (10 mL). Note that some of the product may be present in the aqueous layer. Carefully adjust the pH of the aqueous layer to about 6 with saturated aqueous sodium carbonate, and then extract the product from the aqueous layer with ethyl acetate (10 mL). The organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated in vacuum to afford 2-(Boc-amino)pyridine-4-boronic acid pinacol ester as a white solid (0.44 g, 76% yield). The product was characterized by 1H NMR (DMSO-d6) and LCMS: 1H NMR (DMSO-d6) δ 1.29 (s, 12H), 1.45 (s, 9H), 7.15-7.17 (d, 1H), 8.07 (s, 1H), 8.24-8.25 (d, 1H), 9.77 (s, 1H); LCMS Rt = 0.68 min, MS m/z 183.1 [M+H]+.