Palladium on carbon (10%, 85 mg) was added to 25b (425 mg, 0.729 mmol) in anhydrous THF (4.90 mL) and the solution was placed under an atmosphere of H2. After 12 hours, the solution was filtered through SiO2 (1:1 CH2Cl2:Acetone) and the eluent was concentrated to afford a yellow solid, which was used without further purification (325 mg, 99%). EDCI (116 mg, 0.6026 mmol) and 1H-indole-2-carboxylic acid (77.7 mg, 0.4821 mmol) were added to the amine (108 mg, 0.2410 mmol) in 30% pyridine/CH2Cl2 (6.70 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 3:1 Hexane:Ether→40:1 CH2Cl2:Acetone) to afford a colorless solid, which was used without further purification (91.0 mg, 64%). Triethylamine (150 μL) was added to the carbonate (91.0 mg, 0.1536 mmol) in MeOH (2.5 mL) and CH2Cl2 (2.50 mL). After 48 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 40:1 CH2Cl2:Acetone) to afford 26j as a colorless amorphous solid (17.5 mg, 20%, 13% over 3 steps): 1H NMR (CD2Cl2, 400 MHz) δ 9.32 (s, 1H), 8.80 (s, 1H), 8.76 (s, 1H), 7.77 (d, J=8.0 Hz, 1H), 7.53 (d, J=7.5 Hz, 1H), 7.40-7.36 (m, 1H), 7.24-7.20 (m, 1H), 6.98 (s, 1H), 6.01 (s, 1H), 5.15 (d, J=6.5 Hz, 1H), 4.32-4.25 (m, 1H), 4.11-4.04, (m, 1H), 3.62-3.59 (m, 2H), 3.53 (s, 3H), 3.18-3.12 (m, 1H), 2.64 (s, 1H), 2.49 (s, 3H), 2.18 (s, 1H), 1.95-1.91 (m, 2H), 1.36 (d, J=9.6 Hz, 3H), 1.29 (d, J=9.8 Hz, 3H), 1.12 (t, J=7.4 Hz, 3H); 13C NMR (CDCl3, 125 MHz) δ 160.1, 159.0, 148.8, 146.9, 143.4, 136.9, 129.8, 127.6, 125.5, 123.5, 123.0, 122.6, 122.3, 121.2, 116.0, 112.0, 107.3, 104.3, 102.2, 82.8, 71.0, 70.1, 69.1, 60.2, 59.7, 25.7, 23.1, 23.4, 10.5, 10.2; IR (film) νmax 3630, 3304, 2926, 2854, 2359, 2332, 1713, 1705, 1539, 1387, 1240, 1103, 947, 930, 822, 739 cm−1; HRMS (ESI+) m/z: [M+H]+ calcd for C30H34N2O9, 567.2342. found, 567.2367.
