Synthesis of TEtraQuinoline 8a. A sealed tube was charged with cyclic diamide 5 (98.5 mg, 0.2 mmol), 2,4,6-trimethoxypyridine (169.2 mg, 1 mmol), and dichloroethane (3 mL) under an argon atmosphere. Tf2O (105 μL, 0.64 mmol) was added dropwise at 0 °C, and the resulting mixture was stirred for 15 min. After adding 4-ethynylanisole (6; 0.26 mL, 2 mmol), the resulting mixture was stirred at 80 °C for 22 h. Then, Et3N was added to quench the reaction, and the mixture was filtered through a pad of silica gel (eluent: CH2Cl2/ethyl acetate = 1/1, v/v). The filtrate was concentrated, and the resulting residue was filtered through a longer pad of basic Al2O3 (eluent: CH2Cl2/ethyl acetate = 20/1, v/v). Subsequently, all volatiles were removed under reduced pressure, and the resulting residue was washed seven times with Et2O (using centrifugation to remove the solvent by decanting or pipetting) to afford TEQ 8a (60.2 mg, 42% yield) as a pale-grey solid. The aforementioned Et2O solutions were combined and all volatiles were removed under reduced pressure. The obtained residue was purified by column chromatography on silica gel (Biotage RediSep prepacked column, eluent: hexane/ethyl acetate = 1/1 to 1/3, v/v) to afford a crude product that was washed with a small amount of Et2O to afford an additional 3.0 mg (2% yield) of TEQ 8a.