9-[(E)-2-(4-Chloro­phen­yl)ethen­yl]-3,3,6,6-tetra­methyl-2,3,4,5,6,7,8,9-octa­hydro-1H-xanthene-1,8-dione

In the title compound, C₂₅H₂₇ClO₃, each of the cyclo­hexenone rings adopts an envelope conformation, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating from the plane of the other four atoms. The C=C double bond is in the trans conformation. In the crystal, weak C—H...O hydrogen bonds link the mol­ecules into chains running parallel to the b axis.