In the title compound, C(28)H(27)NO(5)S, the five-membered pyrrolidine ring, which exhibits an envelope conformation (the C atom at the spiral junction being the flap atom), makes dihedral angles of 57.37 (10) and 86.84 (8)°, respectively, with the phenyl ring and the acenaphthyl-ene ring system. In the crystal, mol-ecules associate via two C-H⋯O hydrogen bonds, forming R(2) (2)(20) and R(2) (2)(10) graph-set motifs.