Br[C:2]1[C:6]2[C:7]([NH2:11])=[N:8][CH:9]=[CH:10][C:5]=2[O:4][CH:3]=1.CC1(C)C(C)(C)OB([C:20]2[CH:21]=[C:22]3[C:26](=[CH:27][CH:28]=2)[N:25]([C:29]([O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[O:30])[CH2:24][CH2:23]3)O1.C(=O)(O)[O-].[Na+]>O1CCOCC1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2].C(Cl)Cl>[NH2:11][C:7]1[C:6]2[C:2]([C:20]3[CH:21]=[C:22]4[C:26](=[CH:27][CH:28]=3)[N:25]([C:29]([O:31][C:32]([CH3:35])([CH3:34])[CH3:33])=[O:30])[CH2:24][CH2:23]4)=[CH:3][O:4][C:5]=2[CH:10]=[CH:9][N:8]=1A mixture of 3-bromofuro[3,2-c]pyridin-4-amine (3.002 g, 14.09 mmol), 1,1-dimethylethyl 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1H-indole-1-carboxylate (5.346 g, 15.48 mmol), and PdCl2(dppf)-CH2Cl2 adduct (0.573 g, 0.702 mmol) in 1,4-Dioxane (120 mL) and saturated aqueous sodium bicarbonate (43 mL, 43.0 mmol) was degassed with Nitrogen for 20 minutes. The mixture was then stirred at reflux under Nitrogen for 16 hours. It was then cooled, poured into half-saturated aqueous NaHCO3 (250 mL), and extracted with ethyl acetate (2×250 mL). The extracts were washed with brine (1×250 mL), dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography (Analogix, 400 g SiO2, 20%-100% EtOAc in hexanes gradient over 60 minutes, then 100% EtOAc for 15 more minutes) to give 1,1-dimethylethyl 5-(4-aminofuro[3,2-c]pyridin-3-yl)-2,3-dihydro-1H-indole-1-carboxylate (3.93 g) as an off-white solid. LC/MS (ES) m/z=352 [M+H]+.
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