Thermally induced decarbonylation of cage ketones

3,8-Bis(4-chlorophenyl)-4,7-dimethyltricyclo[4.2.2.02,5]deca-3,7-diene

The title tricyclic diene, C₂₄H₂₂Cl₂, is the product of thermal ring-opening of a corresponding basketane (penta­cyclo­[4.4.0.0^2,5.0^3,8.0^4,7]deca­ne) derivative. The cyclo­butene ring is planar to within 0.0032 (12) Å and its geometry is normal. The two 4-chloro­phenyl groups are oriented in an approximately face-to-face conformation with a dihedral angle of 44.14 (6)° between them. The 4-chloro­phenyl group bonded to the cyclo­butene ring lies almost in the plane of the cyclo­butene ring, with a dihedral angle of 8.29 (17)° between the ring planes. The average intra­molecular C⋯C distance between the two C=C bonds is 2.92 Å. In the crystal structure, the mol­ecules are well separated with no close C—H⋯Cl or C—H⋯π inter­molecular inter­actions.