Experimental probe for hyperconjugative resonance contribution in stabilizing the singlet state of 2,2-dialkoxy-1,3-diyls: Regioselective 1,2-oxygen migration.
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.
Abe
Manabu
M
Department of Applied Chemistry, Graduate School of Engineering, Osaka University (HANDAI), Suita 565-0871, Osaka, Japan. abe@chem.eng.osaka-u.ac.jp
Hattori
Masanori
M
Takegami
Akinobu
A
Masuyama
Araki
A
Hayashi
Takashi
T
Seki
Shu
S
Tagawa
Seiichi
S