title: Structure of diethyl 1,2,3,3b,4a,5,6,7,8,8a,8b,9-dodecahydro-1,5-dioxo-4,8,9-metheno-4H-cycl openta [1,2-a:4,3-a']dipentalene-4,10-dicarboxylate.
abstract: C24H24O6, Mr = 408.45, triclinic, P1, a = 10.276 (2), b = 13.000 (2), c = 7.782 (1) A, alpha = 98.06 (1), beta = 97.63 (1), gamma = 84.43 (1) degree, V = 1017 A3, Z = 2, Dx = 1.33 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 0.89 cm-1, F(000) = 432, T = 296 K, R = 0.048 for 3321 unique reflections with Fo2 greater than 3 sigma(Fo2). Both cyclopentenones are canted in the endo direction (6.0 and 7.9 degrees), the one syn to the ethoxy groups less so for steric reasons. When the ester groups are disregarded, the polyquinane portion of the molecule is seen to possess a non-crystallographic twofold axis. The overall molecular geometry is reconcilable with the absence of any significant alteration in the density maximum of the C--C pi bonds at this level of downward pyramidalization.
authors.affiliation: Evans Chemical Laboratories, Ohio State University, Columbus 43210.
authors.forename: D R
authors.initials: DR
authors.lastname: Lagerwall
authors.forename: J C
authors.initials: JC
authors.lastname: Gallucci
authors.forename: L A
authors.initials: LA
authors.lastname: Paquette
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011083:Polycyclic Compounds / Q000737:chemistry*; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D001952:Bridged-Ring Compounds; D011083:Polycyclic Compounds; C073005:diethyl 1,2,3,3b,4a,5,6,7,8,8a,8b,9-dodecahydro-1,5-dioxo-4,8,9-metheno-4H-cyclopenta(1,2-a:4,3-a')dipentalene-4,10-dicarboxylate