Lithium Chloride → tert-Butyl (2S,4S)-2-(hydroxymethyl)-4-{[(1-isopropyl-1H-indazol-3-yl)carbonyl]amino}pyrrolidine-1-carboxylate

Participants

Reaction Steps

To a stirred solution of 1-tert-butyl 2-methyl (2S,4S)-4-{[(1-isopropyl-1H-indazol-3-yl)carbonyl]amino}pyrrolidine-1,2-dicarboxylate (135 mg, 0.313 mmol, step 1 of Example 7) in tetrahydrofuran-methanol (2 mL-2 mL) were added lithium chloride (81 mg, 1.92 mmol) and sodium borohydride (73 mg, 1.92 mmol) at room temperature. The resulting mixture was stirred at the same temperature for 20 h. Another lithium chloride (81 mg, 1.92 mmol) and sodium borohydride (73 mg, 1.92 mmol) were added to the mixture at room temperature. After stirring for 3 h, the mixture was quenched with water (10 mL), extracted with ethyl acetate (100 mL). The organic layer was washed with brine (10 mL), 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 117 mg (93%) of the title compound as a colorless oil.

Provenance & Evidence