The second talk described below may be of interest *JEOL Postdoc Competition Winners’ Seminar * *Thursday 20th September * *13.00-15.00* *C/A101* *13.00 Dr. Aggie Lawer* *"Synthesis of functionalised peptides/macrocycles and medium-size **rings via stereoselective fluorination and SuRE/NICE chemistry"* Insertion of fluorine into organic molecules is well-known to affect the molecules’ electronic distribution and conformation in ways that can be beneficial in drug development. However, the effects of fluorination have not been widely investigated in the context of peptides, which limits the development of peptide-based drugs. In the first part of the talk, I will discuss how stereoselective fluorination was used to control the conformations of peptides and enhance the potency of a peptide-based enzyme inhibitor. While peptides/macrocycles and medium-size rings have recently gained noteworthy interest in the area of medicinal chemistry, their synthesis is mostly limited to the traditional end-to-end macrocyclisations which suffer from unfavourable thermodynamic factors, and oftentimes require the use of high dilution conditions. In the second part of my talk, I’ll describe how Successive Ring Expansion (SuRE) and N-acyl Iminium ion mediated Cyclisation/Expansion (NICE) reactions developed in Unsworth group could be employed to overcome these limitations, providing an efficient, scalable and practical route to make diverse macrocycles and medium-size rings. *13.45 Dr. Peter Rayner * *"Tunable Hyperpolarisation by Synthetic Design"* NMR and MRI are two of the most popular techniques to study molecules and materials. However, both of these approaches are insensitive and hyperpolarization methods to increase signal size are needed in order to access new applications. This talk will describe how rational synthetic design of both the contrast agents and N-heterocyclic carbene catalysts utilized in the Signal Amplification by Reversible Exchange process, have led to signals that are up to 120,000 times larger than those achieved on a typical hospital scanner and can be observed many minutes after their creation. These improvements have allowed the observation of hyperpolarized molecules by in vivo MRI techniques. *The seminar will be followed at 14.30 by refreshments* -- Antony Morland, PhD. Director, York Neuroimaging Centre Department of Psychology, University of York, York YO10 5DD, UK.