Received 15 July 2008
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)°. The compound crystallizes as centrosymmetric carboxyl dimers [OO = 2.6513 (12) Å and O-HO = 178°], which have two orientations within the cell and contain no significant carboxyl disorder.
Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2213 ).
HWT is grateful to Professor Gree Loober Spoog for helpful consultations. The authors acknowledge support by NSF-CRIF grant No. 0443538.
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