O[CH2:2][C:3]([CH3:14])([CH3:13])[CH2:4][NH:5][C:6](=[O:12])[O:7][C:8]([CH3:11])([CH3:10])[CH3:9].[NH:15]1[C:19]2=[N:20][C:21]([C:24]([O:26][CH2:27][CH3:28])=[O:25])=[CH:22][CH:23]=[C:18]2[CH:17]=[C:16]1[C:29]([O:31][CH2:32][CH3:33])=[O:30].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OC(C)C)=O)=NC(OC(C)C)=O>C1COCC1>[C:8]([O:7][C:6]([NH:5][CH2:4][C:3]([CH3:14])([CH3:13])[CH2:2][N:15]1[C:19]2=[N:20][C:21]([C:24]([O:26][CH2:27][CH3:28])=[O:25])=[CH:22][CH:23]=[C:18]2[CH:17]=[C:16]1[C:29]([O:31][CH2:32][CH3:33])=[O:30])=[O:12])([CH3:11])([CH3:10])[CH3:9]To a solution of tert-butyl (3-hydroxy-2,2-dimethylpropyl)carbamate (2.13 g, 10.5 mmol), diethyl 1H-pyrrolo[2,3-b]pyridine-2,6-dicarboxylate (Intermediate D, 2.50 g, 9.53 mmol), and triphenylphosphine (5.00 g, 19.1 mmol) in THF (15 mL) is added diisopropyl azodicarboxylate (3.95 mL, 19.1 mmol). The reaction is stirred at room temperature for 64 h. The solvent is removed in vacuo and the crude material is purified via silica gel chromatography using a gradient elution of 0-30% ethyl acetate/hexanes to afford the title compound as a yellow oil which crystallized upon standing (4.20 g, 99%). LCMS: 478.86 (M+Na+).
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