Investigating the formation of beta-lactams via asymmetric photochemical Staudinger reactions

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Modern photoredox catalysis aims to achieve chemical transformations which were hitherto impossible using milder reaction conditions and producing less waste than traditional synthetic chemistry. It does this by using visible light (usually blue), along with a small amount of catalyst (usually containing a transition metal), to perform reactions which may have traditionally necessitated the use of large amounts of chemical reagents, and which may have produced large amounts of waste and unwanted byproducts. The impact of this shift to cleaner methods of synthesis is clear - large scale production of necessary chemicals (pharmaceuticals, agrichemicals, etc.) will have a much lower impact on the environment, a key concern in today's environment.This project specifically aims to develop a new method of synthesising beta-lactams. Beta-lactams are commonly found in drug molecules and a whole class of antibiotics including penicillin derivatives (penams) contains this type of structure. These types of structure are usually functionalised (they contain some other types of structure chemically bonded to them) and this gives rise to chirality within the molecule. Most reactions cannot discriminate between forming one form (enantiomer) of a product or another. This is a key issue when only one enantiomer is desired as separation of enantiomers is costly and yields are artificially limited. With this project we wish to develop a method which can discriminate between different enantiomers and produce only the desired one, thereby maximising efficiency and minimising waste. Coupling this with efficient photocatalysis improves the reaction even more and small amounts of catalyst can be used which further minimises waste.While asymmetric photocatalysis is precedented in the literature, many of these make use of two different types of catalyst, increasing the overall amount of catalyst which needs to be used. A number of examples chiral photocatalysts which do not require the use of co-catalysts exist, but these have been used for different purposes and not for chemical structures which are directly relevant to medicinal chemistry and pharmaceuticals. The project will therefore attempt to build on the work done by others in the field on developing chiral photocatalysts and aim to apply it to reactions and reactivity which are directly relevant to challenges faced in modern chemistry.This project falls within the EPSRC Synthetic Organic Chemistry research area.