Competitive β-hydrogen abstraction of “mixed” dialkylzirconocenes and kinetic measurements of decomposition of methyl(alkyl)zirconocenes reveal unexpected relative reactivity of alkyl groups as β-hydrogen donors, such as s-Bu > t-Bu ≥ Et > n-Bu > i-Bu, which correlate well in most cases with the reactivity order of: β-methyl > β-methylene > β-methine. Some mechanistically crucial features of the reaction are also discussed.
竞争性β-氢抽取的“混合”二烷基
锆烯和甲基(烷基)
锆烯的分解动力学测量揭示了烷基作为β-氢供体的相对反应性意外顺序,如s-Bu > t-Bu ≥ Et > n-Bu > i-Bu,这在大多数情况下与反应性的顺序很好地相关:β-甲基 > β-亚甲基 > β-亚
丁烯。文中还讨论了一些反应机制上至关重要的特征。