title: Experimental probe for hyperconjugative resonance contribution in stabilizing the singlet state of 2,2-dialkoxy-1,3-diyls: Regioselective 1,2-oxygen migration.
abstract: A detailed study of the regioselectivity of 1,2-oxygen migration was conducted using the unsymmetrically substituted singlet 2,2-dialkoxy-1,3-diarylcyclopentane-1,3-diyls 5. The alkoxy group selectively migrates to the electron-donating p-methoxyphenyl-substituted carbon. The regioselective migration of oxygen clearly indicates a hyperconjugative resonance structure, that is, zwitterionic characteristics, in singlet 2,2-dialkoxy-1,3-diyls. This represents the first attempt to experimentally probe the contribution of hyperconjugation to stabilizing the singlet state.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka University (HANDAI), Suita 565-0871, Osaka, Japan. abe@chem.eng.osaka-u.ac.jp
authors.forename: Manabu
authors.initials: M
authors.lastname: Abe
authors.forename: Masanori
authors.initials: M
authors.lastname: Hattori
authors.forename: Akinobu
authors.initials: A
authors.lastname: Takegami
authors.forename: Araki
authors.initials: A
authors.lastname: Masuyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Shu
authors.initials: S
authors.lastname: Seki
authors.forename: Seiichi
authors.initials: S
authors.lastname: Tagawa