[n]Radialenes are alicyclic organic compounds containing n cross-conjugated exocyclic double bonds. The double bonds are commonly alkene groups but those with a carbonyl (C=O) group are also called radialenes . For some members the unsubstituted parent radialenes are elusive but many substituted derivatives are known.
Radialenes are investigated in organic chemistry for their unusual properties and reactivity but have not ventured outside the laboratory.
 and radialenes are expected to have a planar molecular geometry with all carbon atoms in the same plane. This is verified experimentally in hexamethylradialene and cyclobutanetetraonetetrakis(hydrazone). Decamethylradialene has a twist envelope geometry with C2 symmetry while a chair conformation is calculated for radialene and found experimentally for hexa-(ethylidene)cyclohexane
Synthesis & properties
Hydrogenation with platinum on carbon gives cis,cis,cis-tetramethylcyclobutane in accordance with the proposed structure. On standing in air at room temperature the compound accepts oxygen and polymerizes.
- Effect of Overcrowding in [n]Radialenes on the Synthesis of BisradialenesMenahem Kaftory, Mark Botoshansky, Shunji Hyoda, Toshihiro Watanabe, and Fumio Toda J. Org. Chem.; 1999; 64(7) pp 2287 - 2292; (Article) doi:10.1021/jo9818
- The Chemistry of Photodimers of Maleic and Fumaric Acid Derivatives. IV.1 Tetramethylenecyclobutane Gary W. Griffin and Laurence I. Peterson J. Am. Chem. Soc.; 1962; 84(17) pp 3398 - 3400; doi:10.1021/ja00876a033