p-Toluenesulfonic acid monohydrate → Methyl (S)-2-benzyloxycarbonylamino-4-oxopentanoate

Participants

Reaction Steps

In a flask under argon was placed (S)-2-benzyloxycarbonylamino-4-oxo-hexanedioic acid 6-t-butyl ester 1-methyl ester (3.04 g, 8.01 mmol), toluene (80 mL) and para-toluene sulfonic acid hydrate (115 mg, 0.61 mmol) and refluxed for 6.5 h and then overnight for 16 h at room temperature. The mixture was concentrated in vacuo and purified by flash column chromatography (silica gel 60, 230-400 mesh; 50% ethyl acetate/hexanes) which afforded (S)-2-benzyloxycarbonylamino-4-oxo-pentanoic acid methyl ester (1.79 g, 80%) as a pale yellow viscous oil.

Provenance & Evidence