85909-08-6

100-58-3

116437-41-3

Step A: Preparation of tert-butyl N-(4-oxo-4-phenylbutyl)carbamate: tert-butyl 2-oxo-pyrrolidine-1-carboxylate (7.03 g, 38 mmol) was dissolved in tetrahydrofuran (130 mL) and cooled to -78°C. Phenylmagnesium bromide (1.0 M solution, 50 mL) was slowly added at -78 °C. The reaction mixture was stirred at -78 °C for 2 h before the reaction was quenched with 2 M hydrochloric acid solution (35 mL). Subsequently, the reaction mixture was slowly warmed to room temperature and the aqueous layer was extracted with ethyl acetate (2 x 100 mL). The organic phases were combined, washed with saturated brine (50 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 9.56 g of the title compound in 96% yield.