Asymmetric Catalysis Using Novel Iron Complexes.

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There is a continual and ongoing requirement to prepare new and more complex molecules, for example as pharmaceutical candidates, agrochemical products and novel materials. In addition, pressures on dwindling resources and energy supplies make it imperative for more efficient routes to be found to known molecules. To achieve these objectives in a sustainable manner, it is necessary to continue to develop more selective and efficient catalysts. These will reduce waste and side-product formation, and have lower energy requirements during use and for subsequent product isolation. This proposal is concerned with the development and evaluation of a series of catalysts for the precise control of the way in which hydrogen atoms are added to specific bonds within a molecule during certain transformations. This process is often an important component of the synthetic approaches to a large proportion of pharmaceutical products and intermediates, agrochemicals and materials. This transformation can often be achieved efficiently using existing catalysts however a drawback of these catalysts is that they are all based on expensive metals, most typically rhodium, ruthenium, iridium and palladium. In addition, the long term security of these very expensive metals is by no means secure and each of them exhibit significant toxicity. For these reasons, there is an increasingly compelling need to reduce the use of precious-metal catalysts in industrial use and to ideally eliminate them fully. In order to address this challenge, this project will focus on the development of catalysts based upon complexes of the transition metal iron, which is known to be a very active for the control of hydrogen addition reactions. Some preliminary related results have already been obtained, which confirm that the proposed synthetic approach to the catalysts is a valid one. The applicant is now set to prepare further extended iron complex derivatives and to test them in hydrogenation reactions. The project will involve the preparation of a broad range of iron-based catalysts with a diverse structure, and these will be tested extensively against a wide range of substrates. Through this process, we shall determine what structural features are most valuable, and which should be avoided. In addition a range of valuable, pharmaceutically-active target molecules will be prepared in order to demonstrate the value of the catalysts.In summary, this project will result in the development of a new class of environmentally friendly, inexpensive and selective catalysts for hydrogen addition to a broad range of substrate classes, thus significantly extending the synthetic power and value of this already pivotal synthetic transformation.