Fig. 2: Library design and synthesis.

a SEL 1 is prepared from two amino acid building blocks decorated with a carboxylic acid. Standard solid-phase amide bond formation protocols result in products with excellent crude purity. b SEL 2, resulting in a benzimidazole scaffold with three decorators, is synthesized in a 7-step procedure. Optimization of all steps and reaction scope for the nucleophilic aromatic substitution and the heterocyclization are reported in detail in Supplementary Figs. 1–3 and summarized in the histograms. c SEL 3 is prepared from an amino acid, and a Suzuki-Miyaura reaction between an aryl bromide and a boronic acid. Cross-coupling optimization and reaction scope for the aryl bromides and boronic acids are reported in detail in Supplementary Figs. 4–6 and summarized in the histograms. d Three high-diversity libraries were prepared from the selected building blocks. For SEL 1, 62 amino acids and 130 carboxylic acids were chosen based on favorable drug-like properties. SEL 2 and SEL 3 used building blocks, which in the reaction scope resulted in a crude product purity > 55%. Selected examples from each library emphasize the chemical diversity of the generated structures. The violin plots show the compliance of our libraries with several parameters important for drug development. Boxplots within the violin plots show the minimum, maximum, median, 75th percentile, and 25th percentile. Source data are provided as a Source Data file.