Under argon, ethyl (diethoxyphosphoryl)acetate (135 mg, 0.6 mmol) was dissolved in anhydrous dimethoxyethane (10 ml). 17.6 mg of NaH (60% in oil) were added at RT to this solution which was stirred at RT for 10 min. Afterward, a solution of 120 mg (0.04 mmol) of (RS)-3-hydroxy-2-(2,2,2-trifluoroethyl)-5-trifluoromethyl-2,3-dihydroisoindol-1-one in anhydrous dimethoxyethane (5 ml) was added and the mixture was subsequently stirred at reflux for 2 h. The reaction solution was left to cool; the reaction solution was then poured onto 50 ml of 5% sodium hydrogencarbonate solution and extracted twice with 20 ml each time of ethyl acetate; the organic phase was dried over MgSO4 and concentrated under reduced pressure, and the residue was purified by chromatography on silica gel using DIP as the eluent. 90 mg (61%) of ethyl (RS)-[3-oxo-2-(2,2,2-trifluoroethyl)-6-trifluoromethyl-2,3-dihydro-1H-isoindol-1-yl]acetate were obtained as a colorless oil which crystallized from heptane as a beige solid.
