α‐ and β‐Eliminations in Transition Metal Complexes: Strategies to Cleave Unstrained C−C and C−F Bonds
Morteza Karimzadeh, Ola F. Wendt
Abstract
Abstract 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(sp 3 )−F and C(sp 3 )−C(sp 3 ) 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.