"Cut and Sew" Transformations via Transition-Metal-Catalyzed Carbon-Carbon Bond Activation

The transition-metal-catalyzed "cut and sew" transformation has recently emerged as a useful strategy for preparing complex molecular structures. After oxidative addition of a transition metal into a carbon-carbon bond, the resulting two carbon termini can be both functionalized in one step via a following migratory insertion and reductive elimination with unsaturated units, such as alkenes, alkynes, allenes, CO, and polar multiple bonds. Three- or four-membered rings are often employed as reaction partners due to their high ring strains. The participation of nonstrained structures generally relies on cleavage of a polar carbon-CN bond or assistance of a directing group.