A cooperative approach to iron-catalyzed C-H functionalization

The development of predictable iron catalysis using well-defined catalysts systems offer the prospect to explore exciting and unique chemical reactivity not observed with canonical precious metals. This reactivity is essential for the advancement of synthetic chemistry and can be attributed to the unique properties of iron. One property which renders designing rational, well-defined catalysts challenging is the propensity of iron to form ill-defined structures under reaction conditions. This research program will deliver the tools necessary to overcome the ill-defined catalyst structures, through the synthesis of well-defined iron complexes centred on tailored boron-based Z-type ligands.
This approach will be exemplified by the development of novel strategies for catalytic C-H functionalization, a waste-free route to high value products from low-cost and widely available starting materials. Despite the high interest, many challenges still remain in C-H functionalization chemistry, in particular, the application of 3d-metal catalysts.
As a result of this challenge and despite the potential of iron-catalyzed C-H functionalizations, there is only a single example of iron-catalyzed C-H functionalization using well-defined complexes, highlighting this as a potentially fruitful and unexplored high impact areas of chemistry. The iron complexes we will utilize contain a weak sigma-type interaction from the metal to the boron and upon exposure to small molecules results in an oxidative addition across the M-B bond. This results in the borane becoming a borohydride by accepting the hydride and thereby facilitating a predictable, formal two electron process at iron.
Initial investigations will establish the viability of these iron complexes towards the activation of C-H bonds in a range of substrates bearing different directing groups which are commonplace in precious-metal catalyzed C-H functionalization chemistry. Exploration will then turn to explore the scope of substrate coupling partners and subsequent catalysis. The development of enantioselective variants of the chemistry will also be a key consideration of the research. This will be achieved by synthesizing borane ligands from commercial chiral pool starting materials in a highly modular approach.

This work is firmly in line with several EPSRC Priority Areas such as Catalysis and Novel and Efficient Chemical Synthesis and maps onto EPSRC "Dial-a-Molecule" Grand Challenge and onto other Priority Areas associated with "Manufacturing the Future" such as Chemical Reactions Dynamics and Mechanism, Chemical Biology and Healthcare Technologies: Diagnostics. Furthermore, the proposed research addresses the EPSRC Sustainable Chemistry Challenge, a key aspect for tomorrow's manufacturing processes.