A 100-mL single-neck round-bottomed flask equipped with a reflux condenser was charged with 162a (170 mg, 0.61 mmol), 3-(acetoxymethyl)-2-(1-oxo-3,4,6,7,8,9-hexahydropyrazino[1,2-a]indol-2(1H)-yl)pyridin-4-ylboronic acid 113i (280 mg, 0.72 mmol), Pd(dppf)Cl2 (30 mg, 0.037 mmol), K3PO4.trihydrate (270 mg, 1.2 mmol), sodium acetate (180 mg, 1.2 mmol), acetonitrile (20 mL), and water (0.5 mL). The system was evacuated and refilled with N2. The reaction mixture was stirred at 100° C. for 2 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the resulting residue was purified by silica-gel column chromatography eluting with 25:1 of dichloromethane/methanol to afford 162b (130 mg, 40%) as a yellow brown solid. MS-ESI: [M+H]+ 540.3
