To a solution of (S)-6-(2-hydroxy-2-methylpropyl)-6-phenyl-3-((S)-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)ethyl)-1,3-oxazinan-2-one (0.729 g, 1.52 mmol) in 1,4-dioxane (16 mL) were added 5-bromo-1-cyclopropylpyridin-2(1H)-one (0.323 g, 1.51 mmol), 2 M aq Cs2CO3 (4 mL), and PdCl2(dppf).CH2Cl2 (0.079 g, 0.0964 mmol). The mixture was degassed and heated, under a nitrogen atmosphere, at 120° C. for 16 h. The mixture was diluted with CH2Cl2, dried over Na2SO4. After the solvents were evaporated, the residue was purified by chromatography on silica gel eluted with MeOH/CH2Cl2 to afford 0.543 g (74%) of (S)-3-((S)-1-(4-(1-cyclopropyl-6-oxo-1,6-dihydropyridin-3-yl)phenyl)ethyl)-6-(2-hydroxy-2-methylpropyl)-6-phenyl-1,3-oxazinan-2-one. LC-MS Method 1 tR=1.41 min, m/z 487 (MH+);
