Methanol → (S)-methyl 4-(tert-butoxycarbonylamino)-5-hydroxypentanoate

Participants

Reaction Steps

To a solution (S)-2-(tert-butoxycarbonylamino)-5-methoxy-5-oxopentanoic acid (26.1 g, 0.1 mol) in THF (500 mL), BH3.Me2S (80 mL, 0.8 mmol) was added dropwise at −78° C., then stirred at rt for 3 hrs. The reaction was stopped by careful addition of methanol. After evaporation and three distillations of methanol, the residue was dissolved in EtOAc, washed with 1 M NaHCO3, and brine. (S)-methyl 4-(tert-butoxycarbonylamino)-5-hydroxypentanoate (12 g, yield 49%) was obtained as an oil that was used in the next step without further purification.

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