Recent advances in machine learning (ML) and computational chemistry have opened the door to the development of hybrid computational workflows for reaction screening and discovery (Fig. 1).[1],[2],[3] In this talk, I will highlight some recent work from our research group in this field. Specifically, I will discuss how we combined automated reaction profile computation with graph neural networks to screen a chemical space of over 5M [3+2] cycloaddition reactions for bioorthogonal click potential, resulting in the identification of over 100.000 plausible click reaction of interest.[4] Furthermore, I will talk about how existing quantum chemical descriptor datasets can be repurposed to construct informative representations for downstream reactivity predictions, enabling extremely data-efficient ML-workflows.2b The latter point will be illustrated for hydrogen atom transfer reactions, where we were able to make informative predictions on datasets as small as a few hundred data points, or even smaller, with our approach. In the final part of my presentation, I will focus on our efforts on the training data generation side, by showcasing our recently developed tool for automated transition state (TS) localization, TS-tools.[6] TS-tools is a Python package that enables transition state searches at xTB or DFT level-of-theory from a reaction SMILES input. On a benchmarking dataset of mono- and bimolecular reaction pathways, TS-tools reaches an excellent success rate of 95% already at xTB level of theory. For tri-/multi-molecular pathways – typically not benchmarked when developing new TS search methods, yet common in various chemical processes, cf. solvent-, auto- and enzyme catalysis – TS- tools retains its abilities, though a DFT treatment becomes essential in many cases.
Figure 1. An overview of a typical workflow associated with machine learning accelerated computational screening.
 Thijs Stuyver