To a solution of 207 (130 mg, 0.246 mmol) in THF (20 mL) at 0° C. was added. DIPEA (0.172 mL, 0.986 mmol) and triphosgene (43.9 mg, 0.148 mmol). The reaction mixture was stirred for 1 hr at 0° C. before cyclopylamine (70.3 mg, 1.232 mmol) was added. The reaction mixture was allowed to warm up to room temperature and stirred for 1 hr before concentration. The residue was purified by Biotage (MeO/DCM, 0-20%, SNAP 25 g cartridge) to give the title compound 208 (104 mg, 0.170 mmol, 69% yield) as a white solid. MS: 611 (MH)+.
