3-Mesityl-2-oxo-1-oxaspiro-[4.4]non-3-en-4-yl 4-chloro-benzoate.

The title compound, C(24)H(23)ClO(4), is a potent insecticide and miticide. The five-membered cyclo-pentane ring displays an envelope conformation with the atom at the flap position 0.611 (2) Å out of the mean plane formed by the other four atoms. The furan ring makes dihedral angles of 71.3 (2) and 81.9 (2)°, respectively, with the 2,4,6-trimethyl-phenyl and 4-chloro-phenyl rings. The dihedral angle between the two benzene rings is 76.6 (1)°. In the crystal, mol-ecules are linked through weak inter-molecular C-H⋯O hydrogen bonds, forming chains running along the c axis.