Potassium Phosphate, Tribasic → 8-Allyl-2-methyl-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of potassium phosphate, tribasic (0.564 g, 2.66 mmol), potassium allyltrifluoroborate (0.197 g, 1.330 mmol), and 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 48 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 (0.25 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 impure material was reconstituted in DMSO (1.0 mL) and purified via preparative mass trigger LCMS using a gradient eluant of 45-70% ACN:0.05% TFA (aq). The collected fractions were combined and the solvent was removed via rotary evaporation to provide the title compound as an off-white solid (0.007 g, 0.030 mmol, 3.41% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.44 (d, J=6.82 Hz, 3H) 3.38-3.42 (m, 2H) 4.82 (q, J=6.82 Hz, 1H) 5.06-5.12 (m, 2H) 5.91-6.01 (m, 1H) 7.28 (d, J=2.02 Hz, 1H) 7.42 (d, J=2.02 Hz, 1H) 9.82 (s, 1H) 10.93 (s, 1H). ESI-MS: m/z 232.2 (M+H)+.

Provenance & Evidence