Ammonium Acetate → Benzyl (2r, 4r)-4-acetoxy-2-(4,5-diphenyloxazol-2-yl)pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of cis-4-hydroxy-N-benzyloxycarbonyl-D-proline 2-oxo-1,2-diphenylethyl ester (7.0 g) and AcONH4 (11.8 g) in AcOH was stirred at 120° C. for 1 hour. The reaction mixture was evaporated, and the residue was dissolved in EtOAc, washed with water, 3N NaOH solution, water and brine, dried (MgSO4), and evaporated in vacuo. The residue was purified by silica gal column chromatography (hexane-EtOAc, 1:1˜2:3 elution) to give first benzyl (2R, 4R)-4-acetoxy-2-(4,5-diphenyloxazol-2-yl)pyrrolidine-1-carboxylate (972.6 mg), then benzyl (2R, 4R)-2-(4,5-diphenyloxazol-2-yl)-4-hydroxypyrrolidine-1-carboxylate (5.12 g).

Provenance & Evidence