No abstract

Selenium (Se) is an emerging versatile player in medicinal chemistry. The incorporation of Se into small molecules and natural products could have multiple benefits. However, the lack of efficient methods for the synthesis of Se-containing chemical library has greatly hindered the development of seleno-medicinal chemistry. With the aim to address this issue, we proposed the development of "clickable selenylation" reactions, which can be used in the synthesis of Se-containing in situ library and DNA-encoded library (SeDEL), thereby quickly producing ultra-large collections of Se-containing compounds and boosting the development of seleno-medicinal chemistry. This research paradigm can be concluded as "clickable selenylation chemistry development!in situ library construction/SeDEL synthesis!phenotype-or target-based screening! seleno-hit compound".

Click chemistry is a concept wherein modular synthesis is used for rapid functional discovery. To this end, continuous discovery of clickable chemical transformations is the pillar to support the development of this field. This report details the development of a clickable C3-H selenylation of indole that is suitable for on-plate parallel and DNA-encoded library (SeDEL) synthesis via bioinspired LUMO activation strategy. This reaction is modular, robust and highly site-selective, and it features a simple and mild reaction system (catalyzed by nonmetallic B(C 6 F 5 ) 3 at room temperature), high yields and excellent functional group compatibility. Using this method, a library of 1350 indole-selenides was parallel synthesized in an efficient and practical manner, enabling the rapid identification of 3 ai as a promising compound with nanomolar antiproliferative activity in cancer cells via in situ phenotypic screening. These results indicate the great potential of this new clickable selenylation reaction in high-throughput medicinal chemistry and chemical biology.

A successful DNA‐encoded library (DEL) will consist of diverse skeletons and cover chemical space as comprehensive as possible to fully realize its potential in drug discovery and chemical biology. However, the lack of versatile on‐DNA arylation methods for phenols that are less nucleophilic and reactive poses a great hurdle for DEL to include diaryl ether, a privileged chemotype in pharmaceuticals and natural products. This work describes the use of “substrate activation” approach to address the arylation of DNA‐conjugated phenols. Diaryliodonium salt, a highly electrophilic and reactive arylation reagent, is employed as Ar+ sources to ensure highly selective on‐DNA arylation of phenols and oximes with both high yields and DNA fidelity. Notably, the new on‐DNA arylation reaction can be applied to the late‐stage modification of peptides containing tyrosine side‐chain and to synthesize DNA‐tagged analogues of existing drug molecules such as sorafenib, a known pan‐kinase inhibitor. The new on‐DNA diaryliodonium salts chemistry affords a greater flexibility in DEL design and synthesis.

No abstract