An 8-mL resealable tube was charged with (2S)-5-cyclobutoxy-1-cyclopropanecarbonyl-2-methyl-6-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1,2,3,4-tetrahydroquinoline (60 mg, 0.15 mmol), tert-butyl 7-bromo-2,3-dihydro-1H-imidazo[1,2-b]pyrazole-1-carboxylate (45 mg, 0.16 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct (11 mg, 0.02 mmol), sodium carbonate (30 mg, 0.28 mmol), 1,4-dioxane (1.5 mL) and water (0.5 mL). The resulting mixture stirred overnight at 80° C. After cooling to room temperature, the reaction mixture was poured into 20 mL of ethyl acetate. The organic layer was separated and washed with water and brine, dried over anhydrous sodium sulfate, filtered and concentrated under vacuum. The residue was purified via column chromatography on silica gel (eluting with 40% ethyl acetate-petroleum ether) to afford tert-butyl 7-((2S)-5-cyclobutoxy-1-(cyclopropanecarbonyl)-2-methyl-1,2,3,4-tetrahydroquinolin-6-yl)-2,3-dihydroimidazo[1,2-b]pyrazole-1-carboxylate (50 mg, 69%) of as a black solid. MS (ESI, pos. ion) m/z 493 [M+H]+.
