rac-syn-Diethyl 2-hy-droxy-4-oxo-1-phenyl-cyclo-hexane-1,2-dicarboxyl-ate.

The title compound, C(18)H(22)O(6), was obtained by the domino oxa-Michael-aldol (DOMA) reaction and has the cyclo-hexa-none ring in a chair conformation with intra-annular torsion angles in the range 49.9 (2)-58.9 (2)°. The two eth-oxy-carbonyl substituents on the cyclo-hexa-none ring adopt a syn configurations. In the crystal, the mol-ecules self-assemble through duplex inter-molecular hy-droxy-carbonyl O-H⋯O hydrogen bonds, giving centrosymmetric cyclic dimers [graph set R(2) (2)(12)] which inter-associate through weak C-H⋯O hydrogen-bonding inter-actions.