Reaction Steps
To a mixture of 3-methyl-4-trifluoromethanesulfonyloxy-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (Preparation #13, 5.07 g, 14.69 mmol), (R)-4-methyl-6-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one (Preparation #11, Step E, 2.8 g, 8.16 mmol) and K3PO4 (3.46 g, 16.32 mmol) in DMF (60 mL) and water (10 mL) was added Pd(Ph3P)4 (3.77 g, 3.26 mmol). The reaction mixture was stirred at 80° C. overnight then cooled to ambient temperature and concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 3-50% EtOAc in petroleum ether) to give 3-methyl-4-((R)-4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (3.5 g) as a yellow liquid. Further purification by prep-HPLC (Table 3, Method 33) ave 3-methyl-4-((R)-4-methyl-3-oxo-2,3,4,10-tetrahydro-9-oxa-1,2,4a-triaza-phenanthren-6-yl)-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (1.5 g, 44%) as a white solid. 1H NMR (CDCl3, 400 MHz): δ 8.03 (brs, 1H), 7.02-6.93 (m, 2H), 6.87 (s, 1H), 5.81 (brs, 1H), 4.77 (q, J=6.8 Hz, 1H), 4.66-4.53 (d, J=13.2 Hz, 2H), 4.47-4.18 (m, 1H), 3.95-3.77 (m, 2H), 3.32 (d, J=13.2 Hz, 1H), 2.79 (brs, 1H), 1.53 (m, 3H), 1.51 (s, 9H), 1.02 (d, J=6.8 Hz, 3H). LC/MS (Table 1, Method 44) Rt=3.339 min.; MS m/z: 414 [M+H]+.
