A solution of #114 (225 mg, 0.356 mmol, 1.0 eq.) in 2 mL of dichloromethane was added to a solution of N-[(9H-fluoren-9-ylmethoxy)carbonyl]-3-methyl-D-isovaline (126 mg, 0.356 mmol, 1.0 eq.) in 4 mL of dichloromethane. Hunig's base (0.188 mL, 1.07 mmol, 3.0 eq.) was added followed by HATU (167 mg, 0.427 mmol, 1.2 eq). The reaction was allowed to stir at room temperature for 12 hours. The reaction was concentrated in vacuo and then taken up in ethyl acetate before being washed two times with 1M HCl and once with brine. The organic layer was dried over sodium sulfate and decanted. The organic solvent was removed in a genevac. THF (4 mL) was added followed diethylamine (2 mL, 19 mmol, 53.4 eq.). The reaction was allowed to stir for ˜12 hours. Reaction was concentrated using a genevac followed by silica chromatography (Gradient: 0%-30% methanol in ethyl acetate) producing #146 (183 mg, 69%) as a solid. LC-MS (Protocol Q): m/z 746.4 [M+H+] retention time=1.37 minutes. 1H NMR (400 MHz, DMSO-d6), δ 8.55 (d), 8.26-8.36 (m), 7.88-8.03 (m), 7.81 (d), 7.41-7.53 (m), 7.13-7.30 (m), 7.01 (s), 4.71-4.79 (m), 4.44-4.70 (m), 3.96-4.04 (m), 3.70-3.80 (m), 3.62-3.69 (m), 3.40-3.61 (m), 2.76-3.35 (m), 2.67-2.71 (m), 2.56-2.58 (m), 2.06-2.46 (m), 1.61-1.90 (m), 1.14-1.54 (m), 0.72-1.12 (m).
