Inner Rotation of the Exocyclic C=C Bonds of Methyl 2-Cyano-(2-methylcyclohepta[<i>b</i>]thiophen-8-ylidene)acetate and Methyl 2-Cyano-(1,2-dimethylcyclohepta[<i>b</i>]pyrrol-8-ylidene)acetate
作者:Yukari Ikeda、Bing Zhu Yin、Nobuo Kato、Akira Mori、Hitoshi Takeshita
DOI:10.1246/cl.1992.1453
日期:1992.8
The rotational barrier of the exocyclic C=C bonds of heptafulvenes condensed with a hetero aromatic ring is dependent on electron donating ability of heterocycles and on the steric repulsion around the exocyclic C=C bond. The large negative entropies of activation are consistent with an extensively polarized transition state.