title: Predominance of the participation of the geminal over vicinal bonds: torquoselectivity of retro-Nazarov reactions.
abstract: Torquoselectivities of electrocyclic ring-opening reactions have been proposed to be controlled by the participation of electron-donating σ-bonds (σ-EDB) geminal to the breaking σ-bond and/or vicinal electron-accepting σ-bonds (σ-EAB) or lone pair(s) of the substituent(s). We designed reactions in which the effects of the vicinal bonds should be significantly diminished by the cationic nature of the reactants. The calculated enthalpies of activation of the retro-Nazarov reactions of some 3-substituted cyclopentenyl cations show inward rotation of the geminal σ-EDB, which is consistent with the theory of geminal bond participation.
authors: Department of Chemistry, Gifu University , 1-1 Yanagido, Gifu 501-1193, Japan.
authors: Yuji
authors: Y
authors: Naruse
authors: Yu
authors: Y
authors: Ichihashi
authors: Takashi
authors: T
authors: Shimizu
authors: Satoshi
authors: S
authors: Inagaki