A vial was charged with (S)-3-bromo-7-iodo-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine, diisopropylamine (0.785 mL, 5.51 mmol), Pd(PPh3)4 (0.127 g, 0.110 mmol), copper(I) iodide (0.021 g, 0.110 mmol), and 3,3-dimethyl-1-butyne (0.203 mL, 1.652 mmol). DMF (3 mL) were added, the vial was sealed under argon and heated to 90° C. for 60 minutes. The reaction mixture was diluted with 2-MeTHF then washed with water. The organics were dried over MgSO4 and concentrated. Purification of the crude residue by column chromatography gave (S)-3-bromo-7-(3,3-dimethylbut-1-ynyl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.120 g, 0.281 mmol, 25.6% yield) as a white solid. Step 2: A vial was charged with (S)-3-bromo-7-(3,3-dimethylbut-1-ynyl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.060 g, 0.141 mmol), 2-fluoropyridin-4-ylboronic acid (0.050 g, 0.352 mmol), potassium phosphate (0.299 g, 1.407 mmol) and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (4.98 mg, 7.04 μmol) Dioxane (2 mL) and water (0.5 mL) were added, the vial was sealed under argon and heated to 80° C. for 1 hour. The reaction mixture was then diluted with 2-MeTHF, dried over MgSO4 and concentrated. Purification of the crude residue by column chromatography [0-100% (95:5 EtOAc/MeOH)/DCM] gave (S)-7-(3,3-dimethylbut-1-ynyl)-3-(2-fluoropyridin-4-yl)-2′,6′-dihydrospiro[chromeno[2,3-b]pyridine-5,3′-[1,4]oxazin]-5′-amine (0.029 g, 0.066 mmol, 46.6% yield) as a yellow solid. [M+H]+=443.0
