Ethyl (E)-3-[1'-ethyl-2-oxo-4'-(phenyl-sulfon-yl)-2H-spiro-[acenaphthyl-ene-1,2'-pyrrolidine]-3'-yl]acrylate.

In the title compound, C28H27NO5S, 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 acenaphthyl­ene ring system. In the crystal, mol­ecules associate via two C—H⋯O hydrogen bonds, forming R22(20) and R22(10) graph-set motifs.