Oxidative addition is the standard process for single-bond activation in transition metal catalysis and it is known to operate for many types of bonds, but challenging σ-bonds e. g. C(sp³)−F and C(sp³)−C(sp³) bonds are the exceptions in this respect. This short review aims at demonstrating how both α- and β-eliminations may be better options for activation of unstrained C−F and C−C single bonds. Selected examples of such eliminations are presented with a mechanistic focus indicating how unstrained and unactivated C−C and C−F bonds can be broken by employing α- and β-eliminations in transition metal hydrocarbyl ligands. Our examples show that the reaction barrier in β-eliminations is controlled by the s-character of the participating bonds where a higher s-character gives a better overlap in the multi-center transition state thereby increasing the reactivity; still β-aryl eliminations can compete with the classical β-hydrogen eliminations in certain cases.

中文翻译：

---

过渡金属配合物中的 α- 和 β-消除：裂解无应变 C-C 和 C-F 键的策略

氧化加成是过渡金属催化中单键活化的标准过程，已知它可用于多种类型的键，但对 σ 键具有挑战性。克。C(sp ³ )-F 和 C(sp ³ )-C(sp ³) 债券是这方面的例外。这篇简短的评论旨在展示 α- 和 β-消除如何成为激活无应变 C-F 和 C-C 单键的更好选择。此类消除的选定示例以机械焦点呈现，表明如何通过在过渡金属烃基配体中使用 α- 和 β-消除来破坏无应变和未活化的 C-C 和 C-F 键。我们的例子表明，β-消除中的反应势垒受参与键的 s 特征控制，其中较高的 s 特征在多中心过渡态中提供更好的重叠，从而增加反应性；在某些情况下，β-芳基消除仍然可以与经典的β-氢消除竞争。