To a solution of tert-butyl 7-bromo-3,4-dihydro-1H-pyrido[4,3-b]indole-2(5H)-carboxylate (0.66 g, 1.9 mmol) in DMF (8 mL) was added NaH (60% weight dispersion in mineral oil, 113 mg, 2.82 mmol) followed by SEMCl (0.50 mL, 2.8 mmol). The reaction was stirred at room temperature until complete. The reaction was quenched with H2O, and the aqueous mixture was extracted with CH2Cl2. The organic phase was washed with H2O and brine and dried over Na2SO4. After filtration and concentration, the residue was dried under vacuum to give tert-butyl 7-bromo-5-((2-(trimethylsilyl)ethoxy)methyl)-3,4-dihydro-1H-pyrido[4,3-b]indole-2(5H)-carboxylate, which and used directly in the next step. To a mixture of tert-butyl 7-bromo-5-((2-(trimethylsilyl)ethoxy)methyl)-3,4-dihydro-1H-pyrido[4,3-b]indole-2(5H)-carboxylate (0.75 g, 1.6 mmol), 4-benzyloxypyridone (0.31 g, 1.6 mmol), 8-hydroxyquilinine (34 mg, 0.23 mmol), K2CO3 (0.26 g, 1.9 mmol) and CuI (45 mg, 0.23 mmol) was added DMSO (6 mL). The reaction mixture was degassed and back-filled with N2. The reaction was stirred at 130° C. overnight. The mixture was cooled and filtered through a layer of Celite. The filtrate was diluted with CH2Cl2, washed with H2O and 5% aqueous LiCl and dried over Na2SO4. The organic solution was filtered and concentrated, and the residue was purified by flash column chromatography (silica gel, 5% CH3OH in CH2Cl2) to give the title compound as a yellow oil (0.12 g, 13%): 1H NMR (500 MHz, CDCl3) δ 7.60 (d, J=8.5 Hz, 1H), 7.44-7.37 (m, 6H), 7.31 (d, J=7.5 Hz, 1H), 7.09 (m, 1H), 6.12 (s, 1H), 6.07 (d, J=6.5 Hz, 1H), 5.40 (s, 2H), 5.07 (s, 2H), 4.65 (m, 2H), 3.86 (m, 2H), 3.51 (t, J=8.0 Hz, 2H), 2.73 (m, 2H), 1.53 (s, 9H), 0.89 (t, J=8.0 Hz, 2H), −0.04 (s, 9H); ESI MS m/z 602 [M+H]+.
