1-(1,1-Dimethylethyl) 2-ethyl (2S)-5-oxo-1,2-pyrrolidinedicarboxylate → (S)-2-tert-Butoxycarbonylamino-5-oxo-hexanoic acid ethyl ester

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Reaction Steps

To a solution of (S)-1-tert-butyl 2-ethyl 5-oxopyrrolidine-1,2-dicarboxylate (7.00 g, 27.4 mmol) in tetrahydrofuran (100 mL) was added methyl Grignard reagent (3M in diethyl ether, 9.60 mL, 28.8 mmol) dropwise for 20 minutes at −78° C., and stirred for 1 hour. After stiffing for 2 hours at 0° C., to the mixture was added saturated sodium bicarbonate water dropwise, and the aqueous layer was extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, and concentrated under reduced pressure to give the title compound (7.60 g, 26.5 mmol, 97%).

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