New Routes to fluorocarbons using fluoroboranes

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Chemistry

Abstract

Fluorinated molecules have risen to the forefront of modern scientific advances. From Teflon to pharmaceuticals (including blockbuster drugs, e.g. Lipitor), the controlled formation of carbon-fluorine bonds has imparted revolutionary biological and structural effects. However, the current methods to form carbon-fluorine bonds generally rely on highly reactive fluorine sources that limit widespread application and use. This grant will develop fluorine sources based on boron-fluorine bonds that enable the formation of carbon-fluorine bonds using new and orthogonal reactivity to current methods. Boron offers a sustainable choice for catalysis with low physiological and environmental toxicity. This makes it an ideal choice for applications in the pharmaceutical and agrichemical sectors. The boron-fluorine bond is usually considered to be relatively inert, but our deep understanding of boron chemistry will enable the reactivity of B-F bonds to be switched on. This project will achieve this by rationally tuning the structure about boron to enable the capture of fluorine from simple, inexpensive stable sources (e.g. MF) and subsequently transfer it to simple and complex molecular frameworks.

Three methods to do this have been identified: 1. Phase-transfer Catalysis; 2. Fluorine transfer and trapping of activated substrates; 3. Transfer of fluorine and boron to unactivated substrates. These methods share a common theme of boron-fluorine bond formation and subsequent fluorine transfer, but they are not inter-reliant. Each method will be developed separately and addresses a different synthetic need. Phase-transfer catalysis will take fluorine from the solid or aqueous (water) phase and transfer it to the reactive, organic phase. The structure about boron will be used to control the position and facial selectivity of the transfer. Fluorine transfer to activated and unactivated substrates will exploit an activated boron-fluorine bond. Key to this will be activation of the boron-fluorine bond on approach to the substrate and the structure about boron will be used to enhance this interaction and ensure boron-fluorine bond activation. All three methods will be used to explore and understand the fundamentals of boron-fluorine bonding, how to effect high yielding fluorine transfer to substrates, and how rational modifications to borane structure can be used to enable new reactivity. All of the methods will culminate in the application of the new reactivity to industry relevant targets - new active pharmaceutical ingredients, agrichemicals and materials precursors.

Publications

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