Predicting and switching the site of heteroaromatic C-H functionalisation

Heterocyclic CH functionalisation reactions have gathered much interest over the last decade as viable green alternatives to classic cross-coupling reactions, requiring fewer steps and producing less waste. Despite the increasing advances in this field, the issue of regioselectivity remains mostly unsolved. Though some direct heterocyclic CH functionalisations do occur selectively at one position, this is often at the "natural site" of reactivity and does not demonstrate any real regiocontrol.

In a recent publication, Bedford et al. proved that it was possible to control the site selectivity of these heteroaromatic CH functionalisation reactions by switching the mechanism the reaction proceeded by. DFT was used to predict the most acidic and electron rich positions of the heterocycle and then these positions were targeted through base assisted deprotonation (BAD) and electrophilic palladation (EP) mechanisms respectively, allowing full regiocontrol between these two positions.

Having proven that this strategy is effective, it is now of interest to apply this to other heterocycles and further evaluate both the predictive capabilities and regiochemical control. This project will undertake preliminary investigations, using DFT to identify the acidic and electron rich sites of other common heterocycles and then subjecting them to the BAD or EP conditions. If this proves successful, the next step will be to target other positions of the heterocycles, exploiting different innate properties to ensure regiocontrol.

Once these investigations are complete, the project will then aim to try and consolidate the vast amount of DFT data that will have been collected and apply machine learning to speed up the computational prediction.

1. PEOPLE: We will train students with skills that are in demand across a spectrum of industries from pharma/biotech to materials, as well as in academia, law and publishing. The enhanced experience they receive - through interactive brainstorming, problem and dragons' den type business sessions - will equip them with confidence in their own abilities and fast-track their leadership skills. 100% Employment of students from the previous CDT in Chemical Synthesis is indicative of the high demand for the skills we provide, but as start-ups and SMEs become increasingly important in the healthcare, medicine and energy sectors, training in IP, entrepreneurship and commercialisation will stimulate our students to explore their own ventures. Automation and machine learning are set to transform the workplace in the next 20 years, and our students will be in the vanguard of those primed to make best use of these shifts in work patterns. Our graduates will have an open and entrepreneurial mindset, willing to seek solution to problems that cross disciplines and require non-traditional approaches to scientific challenges.

2. ECONOMY: Built on the country's long history of scientific ingenuity and creativity, the >£50bn turnover and annual trade surplus of £5 bn makes the British chemical sector one of the most important creators of wealth for the national economy. Our proposal to integrate training in chemical synthesis with emerging fields such as automation/AI/ML will ensure that the UK maintains this position of economic strength in the face of rapidly developing competition. With the field of drug development desperately looking for innovative new directions, we will disseminate, through our proposed extensive industrial stakeholders, smarter and more efficient ways of designing and implementing molecular synthesis using automation, machine learning and virtual reality interfaces. This will give the UK the chance to take a world-leading position in establishing how molecules may be made more rapidly and economically, how compound libraries may be made broader in scope and accessed more efficiently, and how processes may be optimized more quickly and to a higher standard of resilience. Chemical science underpins an estimated 21% of the economy (>£25bn sales; 6 million people), so these innovations have the potential for far-reaching transformative impact.

3. SCIENCE: The science emerging from our CDT will continue to be at the highest academic level by international standards, as judged by an outstanding publication record. Incorporating automation, machine learning, and virtual reality into the standard toolkit of chemical synthesis would initiate a fundamental change in the way molecules are made. Automated methods for making limited classes of molecules (eg peptides) have transformed related biological fields, and extending those techniques to allow a wide range of small molecules to be synthesized will stimulate not only chemistry but also related pivotal fields in the bio- and materials sciences. Synthesis of the molecular starting points is often the rate-limiting step in innovation. Removing this hurdle will allow selection of molecules according to optimal function, not ease of synthesis, and will accelerate scientific progress in many sectors.

4. SOCIETY: Health benefits will emerge from the ability of both academia and the pharmaceutical industry to generate drug targets more rapidly and innovatively. Optimisation of processes opens the way for advances in energy efficiency and resource utilization by avoiding non-renewable, environmentally damaging, or economically volatile feedstocks. The societal impact of automation will extend more widely to the freeing of time to allow more creative working and also recreational pastimes. We thus aim to be among the pioneers in a new automation-led working model, and our students will be trained to think through the broader consequences of automation for society as a whole