Ammonium Chloride → (R)-6-(benzyloxycarbonylamino)-3-(tert-butoxycarbonylamino)-2-hexanone

Participants

Reaction Conditions

Reaction Steps

N-Methoxy-N-methyl-(R)-5-(Benzyloxycarbonylamino)-2-(tert-butoxycarbonylamino)-pentanamide (305) (10 g, 24 mmol) was dissolved in THF (250 mL) and the solution was cooled to −30° C. in a dry-ice acetone bath. MeMgBr (3M in Et2O, 123 mL, 369 mmol) was added drop-wise over 30 minutes. The bath temperature was slowly allowed to increase to 0° C. and then was maintained at 0° C. until TLC showed no further reaction progress (˜80-90% complete). Saturated NH4Cl (aq) was then slowly added to the reaction mixture at 0° C. and the THF was removed under reduced pressure. The resulting aqueous solution was then extracted with EtOAc and the extracts were washed with water and then brine. The residue was then purified by column chromatography (EtOAc/hexanes) to give (R)-6-(benzyloxycarbonylamino)-3-(tert-butoxycarbonylamino)-2-hexanone (306), (6.5 g, 18 mmol, 75% yield).

Provenance & Evidence