Methyl 3,3,6,6-tetramethyl-1,8-dioxo-4,5,7,9-tetrahydro-2H-xanthene-9-carboxylate

The title molecule, C19H24O5, is built by annulation of a half-chair cyclohexenone and a twist-cyclohexenone to a flat 4-H-pyrane boat. In the crystal, molecules are connected via van der Waals interactions and C—H...O hydrogen bonds.