Water → tert-butyl (2S,4R)-4-hydroxy-2-(2-methoxy-2-oxoethyl)pyrrolidine-1-carboxylate

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Reaction Steps

The solution of tert-butyl (2R,4R)-4-{[tert-butyl(dimethyl)silyl]oxy}-2-(cyanomethyl)pyrrolidine-1-carboxylate (7.81 g, 22.9 mmol, step 1 of Example 9) in concentrated hydrochloric acid-acetic acid (50 mL-50 mL) was refluxed for 15 h and concentrated under reduced pressure. The resulting residue was dissolved in 10% hydrochloric acid in methanol (50 mL). The mixture was refluxed for 18 h and concentrated under reduced pressure. To the suspension of resulting residue in dichloromethane (100 mL) were added triethylamine (9.58 mL, 68.7 mmol) and di-tert-butyl dicarbonate (7.50 g, 34.4 mmol) at 0° C. The mixture was allowed to warm to room temperature and stirred for 14 h. To the mixture was added water (100 mL). The organic layer was separated, dried over sodium sulfate, and concentrated under reduced pressure. The resulting residue was chromatographed on a column of silica gel eluting with n-hexane/ethyl acetate (1:1) to give 4.23 g (71%) of the title compound as a colorless oil.

Provenance & Evidence