(5R)-Ethyl 6-benzyl-8,8-dimethyl-7,9-dioxo-1-oxa-2,6-diazaspiro[4.4]non-2-ene-3-carboxylate

In the title compound, C18H20N2O5, the pyrrolidine ring adopts an envelope conformation with the C atom bonded to the methyl groups as the flap. The dihydroisoxazole ring is essentially planar (r.m.s. deviation = 0.041 Å) and forms a dihedral angle of 65.19 (6)° with the phenyl ring. In the crystal, neighbouring molecules are linked into chains along [110] by intermolecular C—H⋯O hydrogen bonds and weak C—H⋯π interactions involving the phenyl ring.