New catalytic methods to functionalize C-H bonds continue to emerge at a rapid pace due to the potential improvements in both atom and step efficiency that these transformations could exhibit over traditional synthetic approaches. We are investigating the use of dual catalyst systems to enable remote functionalization of unactivated C-H bonds (Fig. 1A). Ultimately, we envision designing catalysts that can be incorporated into proteins to control metal reactivity and selectivity. As part of this program, we are exploring the transmetallation of organic fragments between discrete late metal complexes (Fig. 1B) and the compatibility of these relatively unexplored elementary reactions with various dual catalytic C-C bond-forming reactions (Fig. 1C/D), such as direct arylation and olefin hydroarylation. We have also begun investigating the mechanisms of complexes known to promote non-directed C-H functionalization. By understanding the nature of these systems, we hope to identify discrete complexes that can be incorporated into proteins in order to override the substrate control typically relied upon to provide selectivity in reactions catalyzed by these complexes.
Fig. 3. A) General scheme for dual catalytic functionalization of unactivated C-H bonds. B) Transmetallation of ligands between Ir and Pt complexes. C) Pd-catalyzed cross-coupling of organoiridium complexes and aryl iodides. D) Pd-catalyzed, Ir-promoted direct arylation of unactivated arenes.