Triphenylphosphine → methyl 3-({(2S)-2-[(tert-butoxycarbonyl)amino]propyl}oxy)isoxazole-5-carboxylate

Participants

Reaction Steps

To a solution of methyl 3-hydroxyisoxazole-5-carboxylate (20 g), tert-butyl [(1S)-2-hydroxy-1-methylethyl]carbamate (25 g) and triphenylphosphine (55.1 g) in THF (800 mL) was added dropwise a toluene solution (1.9 M, 110 mL) of diisopropyl azodicarboxylate, and the mixture was refluxed for 5 hr. The reaction mixture was allowed to cool to room temperature, and ethyl acetate was added thereto. The mixture was washed with water and saturated aqueous sodium hydrogen carbonate solution, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (25 g).

Provenance & Evidence