methyl (2S)-2-[(2-methylpropan-2-yl)oxycarbonylamino]-4-methylsulfonylbutanoate

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of (S)-methyl 2-(tert-butoxycarbonylamino)-4-(methylsulfonyl)butanoate (2 g, 6.78 mmol) in tetrahydrofuran (50 mL) was cooled to −78° C., to which potassium bis(trimethylsilyl)amide (1.0 M, toluene solution, 15 ml) was added dropwise, and the mixture was stirred at −78° C. for 2 hours and at room temperature for another 2 hours. An aqueous solution of ammonium chloride (1 M) was added, and the mixture was stirred. The reaction mixture was subjected to liquid separation. The resultant organic layer was then washed with water and brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure, and the formed solid was collected by filtration to obtain the title compound. The water layer separated previously was extracted twice with ethyl acetate. The resultant organic layers were combined, washed with water and brine, and dried over anhydrous magnesium sulfate. The ethyl acetate extracts were combined, dried and then concentrated under reduced pressure to obtain the title compound. The combined product was purified by flash column chromatography (ethyl acetate:petroleum ether, 3:1) to afford the title compound (55 mg, yield 22%) as a yellow solid. was added dropwise the mixture was stirred The reaction mixture was subjected to liquid separation The resultant organic layer was then washed with water and brine dried over anhydrous magnesium sulfate The solvent was removed under reduced pressure the formed solid was collected by filtration

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of (S)-methyl 2-(tert-butoxycarbonylamino)-4-(methylsulfonyl)butanoate (2 g, 6.78 mmol) in tetrahydrofuran (50 mL) was cooled to −78° C., to which potassium bis(trimethylsilyl)amide (1.0 M, toluene solution, 15 ml) was added dropwise, and the mixture was stirred at −78° C. for 2 hours and at room temperature for another 2 hours. An aqueous solution of ammonium chloride (1 M) was added, and the mixture was stirred. The reaction mixture was subjected to liquid separation. The resultant organic layer was then washed with water and brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure, and the formed solid was collected by filtration to obtain the title compound. The water layer separated previously was extracted twice with ethyl acetate. The resultant organic layers were combined, washed with water and brine, and dried over anhydrous magnesium sulfate. The ethyl acetate extracts were combined, dried and then concentrated under reduced pressure to obtain the title compound. The combined product was purified by flash column chromatography (ethyl acetate:petroleum ether, 3:1) to afford the title compound (55 mg, yield 22%) as a yellow solid. was added dropwise the mixture was stirred The reaction mixture was subjected to liquid separation The resultant organic layer was then washed with water and brine dried over anhydrous magnesium sulfate The solvent was removed under reduced pressure the formed solid was collected by filtration

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of (S)-methyl 2-(tert-butoxycarbonylamino)-4-(methylsulfonyl)butanoate (2 g, 6.78 mmol) in tetrahydrofuran (50 mL) was cooled to −78° C., to which potassium bis(trimethylsilyl)amide (1.0 M, toluene solution, 15 ml) was added dropwise, and the mixture was stirred at −78° C. for 2 hours and at room temperature for another 2 hours. An aqueous solution of ammonium chloride (1 M) was added, and the mixture was stirred. The reaction mixture was subjected to liquid separation. The resultant organic layer was then washed with water and brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure, and the formed solid was collected by filtration to obtain the title compound. The water layer separated previously was extracted twice with ethyl acetate. The resultant organic layers were combined, washed with water and brine, and dried over anhydrous magnesium sulfate. The ethyl acetate extracts were combined, dried and then concentrated under reduced pressure to obtain the title compound. The combined product was purified by flash column chromatography (ethyl acetate:petroleum ether, 3:1) to afford the title compound (55 mg, yield 22%) as a yellow solid. was added dropwise the mixture was stirred The reaction mixture was subjected to liquid separation The resultant organic layer was then washed with water and brine dried over anhydrous magnesium sulfate The solvent was removed under reduced pressure the formed solid was collected by filtration