Cesium carbonate → tert-butyl((2S)-1-((5-cyclopropyl-5H-chromeno[3,4-c]pyridin-8-yl)oxy)-4-methylpentan-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 8-chloro-5-cyclopropyl-5H-chromeno[3,4-c]pyridine (275 mg, 1.067 mmol) in toluene (3 mL) was added (S)-tert-butyl (1-hydroxy-4-methylpentan-2-yl)carbamate (696 mg, 3.20 mmol), cesium carbonate (427 mg, 1.310 mmol), di-tert-butyl(2′,4′,6′-triisopropyl-[1′,1′-biphenyl]-2-yl)phosphine (272 mg, 0.640 mmol) and palladium (II) acetate (71.9 mg, 0.320 mmol). Nitrogen was bubbled through the reaction mixture for 10 min then the mixture was heated at 80° C. for 12 h. The reaction mixture was cooled to room temperature and filtered through celite. The filtrate was diluted with water (10 mL) and extracted with ethyl acetate (3×15 mL). The combined organic extracts were washed with brine (1×15 mL), dried over sodium sulfate and concentrated under reduced pressure. The crude product was purified via silica gel chromatography (ethyl acetate/pet ether) to give tert-butyl-(2S)-1-(5-cyclopropyl-5H-chromeno[3,4-c]pyridin-8-yloxy)-4-methylpentan-2-ylcarbamate (250 mg, 0.57 mmol, 50% yield). LCMS (ESI) m/e 439.2 [(M+H)+, calcd for C26H35N2O4 439.3]; LC/MS retention time (Method C): tR=2.16 min.

Provenance & Evidence