A mixture of potassium phosphate (0.676 g, 3.19 mmol), (4S,6S)-4-(2-fluoro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-4-(fluoromethyl)-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-amine (8b, 1.428 g, 3.40 mmol), 5-bromo-2-((trimethylsilyl)ethynyl)pyridine (0.270 g, 1.062 mmol) and 1,1-bis[(di-t-butyl-p-methylaminophenyl]palladium(II) chloride (0.038 g, 0.053 mmol) in dioxane/water (5.0/1.2 mL) was heated in microwave reactor at 110° C. for 35 min. The reaction mixture was diluted with water and extracted with DCM three times. The combined organic layers were washed with brine, dried on sodium sulfate, filtered and concentrated. The crude material was purified by silica gel chromatography: 0-100% EtOAc/hexane in 15 min. The product was obtained as an off-white solid. Trituration with hexane afforded the pure product as a white solid (0.22 g, 44% yield). MS m/z=468 [M+H]+. Calculated for C22H22F5N3OSi: 467.5.
