No abstract

High-throughput experimentation (HTE) has revolutionized the pharmaceutical industry, most notably allowing for rapid screening of compound libraries against therapeutic targets. The past decade has also witnessed the extension of HTE principles toward the realm of small-molecule process chemistry. Today, most major pharmaceutical companies have created dedicated HTE groups within their process development teams, invested in automation technology to accelerate screening, or both. The industry's commitment to accelerating process development has led to rapid innovations in the HTE space. This review will deliver an overview of the latest best practices currently taking place within our teams in process chemistry by sharing frequently studied transformations, our perspective for the next several years in the field, and manual and automated tools to enable experimentation. A series of case studies are presented to exemplify state-of-the-art workflows developed within our laboratories.

Challenging couplings of hindered carboxylic acids with non-nucleophilic amines to form amide bonds can be accomplished in high yields, and in many cases, with complete retention of the adjacent stereogenic centers using the combination of N, N, N', N'-tetramethylchloroformamidinium hexafluorophosphate (TCFH) and N-methylimidazole (NMI). This method allows for in situ generation of highly reactive acyl imidazolium ions, which have been demonstrated to be intermediates in the reaction. The reagent delivers high reactivity similar to acid chlorides with the ease of use of modern uronium reagents.

High-throughput (HT) techniques built upon laboratory automation technology and coupled to statistical experimental design and parallel experimentation have enabled the acceleration of chemical process development across multiple industries. HT technologies are often applied to interrogate wide, often multidimensional experimental spaces to inform the design and optimization of any number of unit operations that chemical engineers use in process development. In this review, we outline the evolution of HT technology and provide a comprehensive overview of how HT automation is used throughout different industries, with a particular focus on chemical and pharmaceutical process development. In addition, we highlight the common strategies of how HT automation is incorporated into routine development activities to maximize its impact in various academic and industrial settings.

We report the development of an open-source experimental design via Bayesian optimization platform for multiobjective reaction optimization. Using high-throughput experimentation (HTE) and virtual screening data sets containing highdimensional continuous and discrete variables, we optimized the performance of the platform by fine-tuning the algorithm components such as reaction encodings, surrogate model parameters, and initialization techniques. Having established the framework, we applied the optimizer to real-world test scenarios for the simultaneous optimization of the reaction yield and enantioselectivity in a Ni/photoredox-catalyzed enantioselective crosselectrophile coupling of styrene oxide with two different aryl iodide substrates. Starting with no previous experimental data, the Bayesian optimizer identified reaction conditions that surpassed the previously human-driven optimization campaigns within 15 and 24 experiments, for each substrate, among 1728 possible configurations available in each optimization. To make the platform more accessible to nonexperts, we developed a graphical user interface (GUI) that can be accessed online through a web-based application and incorporated features such as condition modification on the fly and data visualization. This web application does not require software installation, removing any programming barrier to use the platform, which enables chemists to integrate Bayesian optimization routines into their everyday laboratory practices.

The enantioselective α-alkenylation of aldehydes has been accomplished using boronic acids via the synergistic combination of copper and chiral amine catalysis. The merger of two highly utilized and robust catalytic systems has allowed for the development of a mild and operationally trivial protocol for the direct formation of α-formyl olefins employing common building blocks for organic synthesis.

Since being introduced for rangeland improvements in the early to mid-20th century, several non-native grass species have spread beyond their initial planting sites in the American Southwest. Many of these species, especially those that have infiltrated desert ecosystems, can alter fire regimes, which in turn threatens native plant species. In Arizona desert ecosystems, buffelgrass (Pennisetum ciliare) increases fire frequency and intensity, which may create a positive feedback loop, resulting in a shift from native fire-sensitive plant communities to non-native grasslands. Although control efforts are currently underway, a more comprehensive ecosystem approach will be required to treat buffelgrass invasions in southeastern Arizona's deserts. Here, we evaluate the species and environmental factors that may contribute to plant invasion success. We highlight empirical buffelgrass literature as it pertains to invasion, integrate basic invasion ecology theory and restoration ecology to examine potential practical approaches for controlling buffelgrass invasions in southeastern Arizona, and use this information to provide the basis for comprehensive restoration and management. We also briefly discuss public policy related to buffelgrass control in the southwestern United States.

Investigations into nickel-catalyzed borylation reactions have led to the development of an experimental design of 24 reaction conditions for rapid lead identification. A case study on the borylation of a model aryl bromide with B 2 (OH) 4 prompted a series of mechanistic and stability studies to better understand the catalytic cycle and factors that affect robustness. HTEx was employed to study the effect of a series of scavengers on the remediation of nickel from the reaction stream. These combined results have generated an increased understanding of nickel-catalyzed borylation reactions and set the stage for their expanded use in process chemistry.