Sodium hydride → tert-butyl (2S)-2-(oxiran-2-yl)pyrrolidine-1-carboxylate

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Reaction Conditions

Reaction Steps

DMSO (20 ml) was added to sodium hydride (60% NaH, 1.55 g), and the mixture was stirred at 70° C. for 1 hour. The reaction mixture was cooled to room temperature and THF (20 ml) was added. The mixture was cooled to -5° C. , and thereto was dropwise added trimethylsulfonium iodide (7.90 g) in DMSO (30 ml) over 3 minutes. After stirring for 1 minute, t-butoxycarbonyl-L-prolinal (5.13 g) in THF (15 ml) was added quickly, followed by stirring at room temperature for 1 hour. The reaction mixture was poured into ice water (300 ml) and extracted with chloroform. The organic layer was washed with saturated brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel column chromatography (eluate: hexane-ethyl acetate) to give two kinds of diastereomers of (2S)-1-(t-butoxycarbonyl)-2-(1,2-epoxyethyl)pyrrolidine, 3.12 g of its less polar compound and 1.28 g of its more polar compound. (Configuration of the epoxy moiety of the both unidentified.) The less polar compound was used in the following reactions.

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