N,N'-Dihydroxypyromellitimide

Typical Procedure: To a solution of 4-phenylbutyl benzoate (55.6 mg, 0.219 mmol) and NDHPI (1.36 mg, 0.00547 mmol) in MeCN (2.2 mL) is added F-TEDA-BF₄ (155 mg, 0.438 mmol) at room temperature. The mixture is degassed by freeze-thaw for 3 times under Ar atmosphere, and stirred at 50 °C for 5 h. The reaction mixture is then neutralized with saturated aqueous NaHCO₃, and extracted with EtOAc (3 mL×3). The combined organic layers are dried over Na₂SO₄, and concentrated. The residue is purified with flash column chromatography (silica gel, hexane : Et₂O=30 : 1) to provide 4-benzoyloxy-1-phenylbutyl fluoride (43.1 mg, Y. 72%).