Unsaturated dodecahedranes--in quest of the C20H14 1,4,16-triene and C20H12 1,4,10(14),16-tetraene, and their cations and anions.

The highly pyramidal, highly strained 1,4,16-dodecahedratriene (4) and C20H12 1,4,10(14),16-dodecahedratetraene (5) are cage olefins with an intriguing "inner life". For 5 DFT calculations give information about the energetic and geometrical consequences of one-/two-electron oxidation and reduction. Attempts to prepare 4 and 5 through thermal retro[2+2]/[4+2]cycloaddition strategies proved unsuccessful.

σ-Bishomoconjugation (σ-Bishomoaromaticity) in 4C/3(2)e Cations-Scope and Limitations.

For the seco-dodecahedradiene 1, in which the distance d between the carbon atoms of the two double bonds ranges from 2.90 to 3.20 Å and pyramidalization angles Φ range from 14.