(2-((((9H-fluorene-9-yl)methoxy)carbonyl)amino)acetamido)methyl acetate (7.36 g, 20.0 mmol), THF, and p-toluenesulfonic acid monohydrate (0.38 g, 2.00 mmol) were added to a single-neck bottle at 0°C. Benzyl glycolate (6.65 g, 40.0 mmol) was added dropwise and the temperature was naturally raised to room temperature for 2-4h. TLC monitoring this reaction. After the reaction was completed, saturated NaHCO3 solution was added to quench the reaction, extracted with ethyl acetate, and washed with saturated sodium chloride solution. After dried over anhydrous sodium sulfate, filtered, concentrated, and the residue was purified by column chromatography to obtain 7,10-Dioxa-2,5-diazaundecanoic acid, 4,9-dioxo-11-phenyl-, 9H-fluoren-9-ylmethyl ester.
