FluoroCAT · Catalytic C–F Bond Functionalisation with Transition Metal Catalysis

Catalytic C–F Bond Functionalisation with Transition Metal Catalysis

What is the problem being addressed? Fluorinated organic molecules play a pivotal role in chemical manufacture. For example, it has been estimated that approximately 20-40% of pharmaceuticals and agrochemicals contain at least one fluorine atom. Fluorinated organic molecules are also widely applied in materials such as those found in liquid crystal displays. Despite the fact that perfluoroarenes - aromatic hydrocarbons in which every hydrogen atom is replaced with a fluorine atom - are an inexpensive abundant chemical feedstock they are rarely used in chemical manufacture. The strong carbon–fluorine bond provides an impasse to further chemical reactions. Here we propose to develop a new catalytic method to transform inert carbon–fluorine bonds in perfluoroarenes to reactive carbon–aluminium bonds. We will transform the aluminium-containing reactive intermediates into useful products through carbon–carbon and carbon–heteroatom bond forming reactions. Why is it important for society? The overall process represents an original underpinning technology to transform inert and chemically persistent fluorinated molecules into building blocks that can be used in chemical manufacture. The new chemical methods are important for society as they can be used in the production of pharmaceuticals, agrochemicals and materials. Objectives: The overall objectives of this work is to create a fresh paradigm for using perfluoroarenes in pharmaceutical and agrochemical programmes. The long-term benefits will be felt in the areas of health and food sustainability. The proposed programme will provide world-class training in the areas of organometallic chemistry, homogeneous catalysis and mechanistic analysis. Conclusions: Over the course of this grant we discovered two new methods to transform inert carbon–fluorine bonds into carbon–aluminium bonds. The first relies on the use of a high energy aluminium(I) complex which readily undergoes oxidative addition of C–F bonds of fluoroarenes, fluoroolefins and fluoroalkanes. The second method originates from a structurally related aluminium(III) dihydride and requires a palladium bis(phosphine) complex to catalyse C–F bond activation. As part of these studies we have also investigate the interaction of aluminium(III) hydrides, and related zinc(II) and magnesium(II), species with transition metal complexes. These detailed investigations into the organometallic chemistry have led to an understanding of the trajectory of approach of a zinc hydride bonds to transition metal fragments and the solution dynamics of new types of complexes containing three metal atoms bridged by two hydrogen atoms.

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