(3R,4S,5S)-5-BENZYL-4-HYDROXY-3-[1(S)-(1,1-DIMETHYLETHOXYCARBONYLAMINO)-2-PHENYL-ETHYL]PYRROLIDIN-2-ONE

The title compound, tert-butyl {1(S)-[(3R,4S,5S)-5-benzyl-4-hydroxy-2-oxo-3 -pyrrolidinyl]-2-phenylethyl}carbamate, C24H30N2O4, is an example of an all-cis trisubstituted pyrrolidin-2-one. The absolute configurations of the C atoms in the lactam ring were assigned to be 3R, 4S and 5S relative to the known chirality, 1S, of the C-alpha atom of the L-phenylalanine fragment in the compound. There is one intramolecular hydrogen bond between the pyrrolidin-2-one carbonyl O atom and the N-H group of the L-phenylalanine fragment [N-H ... O 2.936(5) Angstrom].