Fundamental Reactions to Cleave Carbon–Carbon σ-Bonds with Transition Metal Complexes

Transition metal-catalyzed reactions proceed through multiple elementary steps in general and, consequently, the mechanisms are often complicated, especially when backbone structures are reconstructed through a sequence of cleavage and formation of C–C bonds. A step-by-step understanding of elementary steps would be valuable to understand such catalytic transformations. This chapter focuses on elementary steps during which carbon–carbon σ-bonds are cleaved by means of organometallic complexes. An elementary step to cleave C–C bonds is a reverse process of a C–C bond forming process. Oxidative addition of a C–C bond to a low-valent transition metal complex is a reverse process of reductive elimination, which occurs with a high-valent diorganometal, forming a C–C bond. β-Carbon elimination is a reverse process of insertion of an unsaturated bond into a carbon–metal bond, that is, carbometallation, or 1,2-addition of an organometal across a double bond. Such fundamental reactions are described along with typical examples. Besides this chapter, there are some excellent reviews on C–C bond cleavage available [1].