To a suspension of potassium phosphate, tribasic (0.564 g, 2.66 mmol), potassium benzyltrifluoroborate (0.263 g, 1.330 mmol), 8-chloro-2-methyl-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-carbaldehyde 15 (0.2 g, 0.886 mmol) in toluene (Ratio: 5.00, 20 mL) and water (Ratio: 1.000, 4.0 mL) was added PdOAc2 (0.015 g, 0.066 mmol) and dicyclohexyl(2′,6′-diisopropoxybiphenyl-2-yl)phosphine (0.062 g, 0.133 mmol) at 23° C. The reaction was stirred at 115° C. for 20 hr. The reaction mixture was poured into water (2 mL) and extracted with Et2O (3×5 mL). The organic layer was dried over Na2SO4, filtered, and the organic phase stripped to dryness via rotary evaporation. The resulting crude material was reconstituted in DCM (1.0 mL) and purified via medium pressure chromatography using a gradient eluant of 1-5% MeOH:DCM. The appropriate fractions were combined and solvent was removed via rotary evaporation. The late eluting fractions were dried in vacuo to provide a yellow solid. The yellow solid was re-suspended in IPA (1.0 mL), heated at reflux to furnish a solution, cooled to room temperature, filtered, rinsed with IPA, and dried in vacuo to provide the title compound as an off-white solid (0.0704 g, 0.250 mmol, 28.2% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.36 (d, J=6.82 Hz, 3H) 3.98 (s, 2H) 4.75-4.81 (m, 1H) 7.16-7.32 (m, 6H) 7.45 (d, J=2.02 Hz, 1H) 9.80 (s, 1H) 10.93 (s, 1H). ESI-MS: m/z 282.2 (M+H)+. mp=163.2-166.1° C.
