(+/-)-Trans-3-Benzoylbicyclo[2.2.2]Octane-2-Carboxylic Acid

The title keto acid, C16H18O3, displays significant twisting of all three ethylene bridges in its bicyclo[2.2.2] octane structure owing to steric interactions; the bridgehead-to-bridgehead torsion angles are 13.14 (12), 13.14 (13) and 9.37 (13)degrees. The compound crystallizes as centrosymmetric carboxyl dimers [O center dot center dot center dot O = 2.6513 (12) angstrom and O-H center dot center dot center dot O = 178 degrees], which have two orientations within the cell and contain no significant carboxyl disorder.