A 25-mL round-bottom flask was charged with (S)-methyl 5-cyclobutoxy-2-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydroquinoline-1(2H)-carboxylate (0.100 g, 0.25 mmol), 1-(3-(benzyloxy)cyclobutyl)-4-iodo-1H-pyrazole (0.106 g, 0.30 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane adduct (0.020 g, 0.02 mmol), sodium carbonate (0.053 g, 0.50 mmol), 1,4-dioxane (10 mL) and water (3 mL). The resulting mixture was stirred overnight at 80° C., and then cooled to room temperature. The reaction mixture was diluted with ethyl acetate (20 mL), washed with water (10 mL) and brine (10 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified via column chromatography on silica gel (gradient elution with 1-10% ethyl acetate/petroleum ether) to afford (S)-methyl 6-(1-(3-(benzyloxy)cyclobutyl)-1H-pyrazol-4-yl)-5-cyclobutoxy-2-methyl-3,4-dihydroquinoline-1(2H)-carboxylate (0.060 g, 48%) as a yellow solid. MS (ESI, pos. ion) m/z 502 [M+H]+.
