Bismuth Redox Catalysis for C–C Coupling Reactions

Formation of CC bonds through transition metal-catalyzed cross-coupling represents the cornerstone strategy to build chemical complexity in a myriad of contexts, spanning from academic laboratories to industrial settings. These remarkable reactions generally proceed through three elementary steps oxidative addition, transmetallation and reductive elimination which couple two organic fragments together using transition-metal complexes as redox-active catalysts. Very recently, bismuth a main-group element has been found to take part in this type of redox events, resulting in the formation of different Cheteroatom bonds, or in H-transfer processes. However, the use of bismuth redox catalysis to forge the highly coveted and synthetically relevant CC bond remains elusive.In this project, we aim to harness this novel redox behavior of bismuth complexes to unlock the unprecedented bismuth-catalyzed CC cross-coupling full catalytic cycle between organic electrophiles and organometallic nucleophiles. For this, we propose the design of a low-valent bismuth(I/III) redox platform, which would cycle through the three key steps of a classical transition metal-mediated coupling. This will involve the study and optimization of challenging processes (such as an unprecedented CC reductive elimination at a bismuth(III) center), which will be approached through a combination of careful ligand design, experimental/theoretical mechanistic analysis, and combinatorial screenings.Besides the conceptual breakthrough derived from such discovery, this idea will be used to implement bismuth-catalyzed cross-coupling reactions as competent, cheaper, and less toxic alternatives to traditional methods based on transition-metal catalysis. Furthermore, the unique properties of bismuth as a main-group redox catalyst could potentially combine advantages of both early and late transition metals, resulting in the development of more versatile catalytic systems.