Crystal structure of (E)-4-ethyl-2-(4-meth­oxy­benzyl­idene)-3,4-di­hydro­naphthalen-1(2H)-one

In the title compound, C(20)H(20)O(2), the exocyclic C=C double bond has an E conformation. The ethyl substituent on the cyclo­hexa­none ring is in an axial orientation. The cyclo­hexa­none ring adopts a screw-boat conformation, with the methyl­ene C atom and the C atom bearing the 4-meth­oxy­benzyl­idene group displaced from the other atoms by 0.812 (1) and 0.334 (1) Å, respectively. The dihedral angle between the planes of the benzene rings is 42.20 (8)°. In the crystal, no directional inter­actions beyond van der Waals contacts are observed.