The title keto acid, C(16)H(18)O(3), displays significant twisting of all three ethyl-ene bridges in its bicyclo-[2.2.2]octane structure owing to steric inter-actions; the bridgehead-to-bridgehead torsion angles are 13.14 (12), 13.14 (13) and 9.37 (13)°. The compound crystallizes as centrosymmetric carboxyl dimers [O⋯O = 2.6513 (12) Å and O-H⋯O = 178°], which have two orientations within the ce...

The title compound, C(20)H(30)O(2), is an ent-atisane diterpenoid which was isolated from the roots of Euphorbia kansuensis. The mol-ecule contains five six-membered rings, among which three six-membered rings of the bicyclo-[2.2.2]octane unit adopt boat conformations and two cyclo-hexane rings adopt chair conformations. In the crystal structure, mol-ecules are connected by inter-molecular O-H⋯...

A bicyclo[2.2.2]octane derivative containing both a tertiary amide and a methyl ester (1) was shown crystallographically to adopt a conformation in which the amide is in the cis configuration, which is sterically disfavored, but electronically favored. The steric strain induces a significant torsion (15.91) of the amide, thereby greatly increasing the solvolytic lability of the amide to the ext...

[structure: see text] Biogenetically interesting polypropionate-derived metabolites 1 and 2, featuring an unprecedented skeleton, have been isolated from the sea slug Elysia diomedea. Their enantiomeric character indicates that the current spontaneous electrocyclization cascade biogenetic hypothesis for the bicyclo[4.2.0]octane core must be enzymatically aided. These compounds are isomeric with...

The first total syntheses of (-)-trichorabdal A and (-)-longikaurin E are reported. A unified synthetic strategy is employed that relies on a Pd-mediated oxidative cyclization of a silyl ketene acetal to generate an all-carbon quaternary center and build the bicyclo[3.2.1]octane framework. These studies, taken together with our previous synthesis of (-)-maoecrystal Z, demonstrate that three arc...

Asymmetric rotators with a 1,4-bis(ethynyl)bicyclo[2.2.2]octane (BCO) core are needed for engineering crystalline arrays of functional molecular rotors. Their synthesis uses carbinol, 2-methyl-3-butyn-2-ol, as a protecting group because of its polar character and its ability to sustain orthogonal functionalization with the further advantage of being readily removed. The synthesis in good yields...

In the structure of the title compound, C(20)H(34)O(2)Si, a cis,trans,cis,cis-[4.5.5.5]fenestrane derivative, the geometry of the central C(C)(4) substructure shows considerable distortion from an ideal tetra-hedral arrangement towards planarity, with two opposite bridgehead bond angles of 128.87 (18) and 122.83 (17)°. The other bridgehead angle of the trans-bicyclo-[3.3.0]octane subunit is als...

The asymmetric unit of the title compound (C6H14N2)[CdCl4]·H2O contained one 1,4-di-aza-bicyclo-[2.2.2]octane dication, a tetrahedral CdCl4 (2-) anion and a lattice water mol-ecule. In the crystal, the solvate water mol-ecule inter-acts with the cationic and anionic species via N-H⋯O and O-H⋯Cl [O⋯Cl = 3.289 (7) Å] hydrogen-bond inter-actions, respectively, leading to a layered supramolecular s...