(2S*,4S*,5R*)-4-methyl-2-[(5S*)-3-methyl-4,5-dihydroisoxazol-5-yl]-5- phenyl-3-(toluene-4-sulfonyl)oxazolidine.

The title compound, C21H24N2O4S, containing 2-isoxazoline and oxazolidine moieties, was studied in order to determine its relative configuration, which could not be determined unambiguously by NMR techniques. The results have shown that the substituents on the three C atoms of the oxazolidine cycle are all on the same side of the ring, while the aromatic group of the toluene-4-sulfonate substituent on the N atom is located on the opposite side. The 2-isoxazoline ring was found to have the 5'S* configuration.