Cesium carbonate → (S)-6-(2-hydroxy-2-methylpropyl)-3-((S)-1-(4-(4-methyl-5-oxo-4,5-dihydropyrazin-2-yl)phenyl)ethyl)-6-phenyl-1,3-oxazinan-2-one

Participants

Reaction Steps

A mixture 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 (279 mg, 0.6 mmol) and 5-chloro-1-methyl-1H-pyrazin-2-one (70 mg, 0.5 mmol), Pd(Ph3P)2Cl2 (3 mg), and aq. Cs2CO3 solution (0.5 mL, 2M) in 1,4-dioxane (3 mL) was stirred at reflux for 2.5 h under N2. When the reaction was over, the mixture was washed with water, and extracted with EtOAc. The organic phase was washed with brine, dried over Na2SO4, filtered, and concentrated to give the crude product, which was purified by preparative TLC to give (S)-6-(2-hydroxy-2-methylpropyl)-3-((S)-1-(4-(4-methyl-5-oxo-4,5-dihydropyrazin-2-yl)phenyl)ethyl)-6-phenyl-1,3-oxazinan-2-one (165.1 mg, 34.6%). LC-MS Method 2 tR=1.107 min, m/z=404.1; 1H NMR (CDCl3): δ 1.11 (s, 3H), 1.18 (s, 3H), 1.54 (d, 3H), 2.35 (m, 4H), 2.87 (m, 1H), 3.62 (s, 3H), 5.69 (m, 1H), 7.05 (d, 2H), 7.34 (m, 5H), 7.45 (m, 1H), 7.50 (d, 2H), 8.25 (s, 1H).

Provenance & Evidence