(E)-2,2-Dimethyl-5-(3-phenylallylidene)-1,3-dioxane-4,6-dione

The title compound, C15H14O4, was prepared by the reaction of 2,2-dimethyl-1,3-dioxane-4,6-dione and (Z)-3-phenylacrylaldehyde in ethanol. The dioxane ring is in a sofa conformation with the C atom bonded to the two methyl groups forming the flap. With the exception of the flap atom and the methyl group C atoms, all other non-H atoms are essentially planar, with an r.m.s. deviation of 0.067 (1) . The crystal structure is stabilized by weak intermolecular C—H...O hydrogen bonds.