To a mixture of Pd(PPh3)4 (255.0 mg, 220.6 μmol), tert-butyl 5-bromo-3-iodo-1H-indole-1-carboxylate (1000 mg, 2369 μmol) and CuI (546.2 mg, 2868 μmol) was added DMF (12 mL) followed by 4-(6-(tributylstannyl)pyridin-2-yl)morpholine (1000 mg, 2206 μmol). The mixture was heated at 100° C. for 20 min. After cooled to RT, the reaction was added H2O (5 mL) and DCM (5 mL). The organic layer was separated. The aqueous layer was extracted with DCM (10 mL×2). The organic layers were combined, dried with sodium sulfate, filtered and evaporated to dryness. The brown crude oil was purified with silica gel chromatography (eluting with 100% DCM) to give tert-butyl 5-bromo-3-(6-morpholinopyridin-2-yl)-1H-indole-1-carboxylate (537.3 mg, 53.13%) as a white solid. MS (ESI, pos. ion) m/z: 458 (M+1). 1H NMR (400 MHz, DMSO-d6) ppm 1.66 (s, 9H), 3.50-3.62 (m, 4H), 3.74-3.83 (m, 4H), 6.80 (d, J=8.4 Hz, 1H), 7.33 (d, J=7.4 Hz, 1H), 7.54 (dd, J=8.9, 2.1 Hz, 1H), 7.64 (dd, J=8.4, 7.6 Hz, 1H), 8.06 (d, J=9.0 Hz, 1H), 8.29 (s, 1H), 8.68 (d, J=2.2 Hz, 1H)
