Bimolecular Homolytic Substitution (SH2) at a Transition Metal

Abstract Transition metal‐catalyzed cross‐coupling reactions have become a powerful and widely used synthetic approach for the construction of both carbon‐carbon and carbon‐heteroatom bonds. These reactions have revolutionized synthetic chemistry by enabling the efficient formation of complex molecular architectures. Among the various methods available, the bimolecular homolytic substitution (S H 2) reaction has emerged as an attractive and versatile method for the formation of C(sp 3 )−C(sp 3 ) and C(sp 3 )‐heteroatom bonds. In recent years, significant progress has been made in the development of radical S H 2 reactions, particularly those involving different transition metal complexes such as cobalt, nickel, and iron. These advancements have expanded the scope of S H 2 reactions, allowing for greater diversity in substrate compatibility and reaction conditions. In this review, we aim to highlight the latest breakthroughs and mechanistic insights into radical S H 2 reactions, focusing on the role of transition metal catalysts in facilitating these transformations. We will discuss the various types of transition metal complexes that have been employed, the mechanistic pathways involved, and the potential applications of these reactions in the synthesis of complex organic molecules.