3-Mesityl-2-oxo-1-oxaspiro-[4.4]non-3-en-4-yl 2-(4-chloro-phen-yl)-3-methyl-butyrate.

In the title compound, C(28)H(31)ClO(4), the five-membered cyclo-pentyl ring displays an envelope conformation with the atom at the flap position 0.519 (3) Å out of the mean plane formed by the other four atoms. The furan ring makes dihedral angles of 72.9 (1) and 82.4 (1)°, respectively, with the trimethyl- and chloro-phenyl rings. The dihedral angle between the two benzene rings is 15.3 (1)°. In the crystal, mol-ecules are linked through inter-molecular C-H⋯Cl hydrogen bonds, forming a chain running along the b axis.