A mixture of (E)-diisopropyl diazene-1,2-dicarboxylate (4.72 g, 23.36 mmol) and triphenylphosphine (6.13 g, 23.36 mmol) in THF (100 mL) was stirred for 15 min, and a solution of (5,7-difluoroquinolin-6-yl)methanol (3.80 g, 19.47 mmol) and isoindoline-1,3-dione (3.15 g, 21.42 mmol) in THF (200 mL) was added dropwise. The reaction mixture was heated at 40° C. for 24 h. After cooling and evaporating, the residue was purified by silica gel with hexane:EtOAc to provide 2-(5,7-difluoroquinolin-6-ylmethyl)isoindoline-1,3-dione (5.10 g, 81%). 1H-NMR (400 MHz, CDCl3) δ ppm 8.93 (m, 1H), 8.39 (m, 1H), 7.85 (m, 2H), 7.72 (m, 2H), 7.59 (d, 1H), 7.43 (m, 1H), 5.15 (s, 2H).
