In the title mol­ecule, C21H19ClO3, the cyclo­hexene ring adopts an envelope conformation, with all substituents equatorial. The plane through its five coplanar atoms makes dihedral angles of 12.75 (14) and 74.16 (8)° with the phenyl and benzene rings, respectively. The dihedral angle between the latter two rings is 81.73 (12)°. Inter­molecular C—H⋯O hydrogen bonds and intra­molecular C—H⋯Cl contacts are found in the crystal structure; a weak C—H⋯π inter­action is also present.

Nine 3-aryl-5r-aryl-6t-carbethoxycyclohex-2-enones 2a-2i have been synthesized. For all these compounds, (1)H and (13)C NMR spectra have been recorded. For two compounds, 2D spectra have been recorded. The spectral data suggest that these compounds adopt sofa conformation in solution with H-5, H-6 and H-4t occupying axial-like positions and H-4c occupying equatorial-like positions. In 3-phenyl-5r-(o-chlorophenyl)-6t-carbethoxycylohex-2-enone (2b), the o-chlorophenyl group is oriented such that the chlorine atom is in between H-4c and H-5. Allylic coupling of H-2 is observed only with H-4t. Evidence has been obtained for four-bond coupling between 1,3-diaxial and 1,3-axial-equatorial protons.

In the title compound, C21H19BrO3, the cyclo­hexene ring adopts an envelope conformation, with all substituents equatorial. The plane through its five coplanar atoms makes dihedral angles of 28.88 (10) and 71.94 (10)° with the bromo­benzene and phenyl rings, respectively. The dihedral angle between the latter two rings is 51.49 (15)°. Inter­molecular C—H⋯O hydrogen bonds are found in the crystal structure; a C—H⋯π inter­action is also present.

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