Accelerating PROTACs Discovery Through a Direct‐to‐Biology Platform Enabled by Modular Photoclick Chemistry

Abstract Proteolysis targeting chimeras (PROTACs) have emerged as a promising strategy for drug discovery and exploring protein functions, offering a revolutionary therapeutic modality. Currently, the predominant approach to PROTACs discovery mainly relies on an empirical design–synthesis–evaluation process involving numerous cycles of labor‐intensive synthesis‐purification and bioassay data collection. Therefore, the development of innovative methods to expedite PROTAC synthesis and exploration of chemical space remains highly desired. Here, a direct‐to‐biology strategy is reported to streamline the synthesis of PROTAC libraries on plates, enabling the seamless transfer of reaction products to cell‐based bioassays without the need for additional purification. By integrating amide coupling and light‐induced primary amines and o‐nitrobenzyl alcohols cyclization (PANAC) photoclick chemistry into a plate‐based synthetic process, this strategy produces PROTAC libraries with high efficiency and structural diversity. Moreover, by employing this platform for PROTACs screening, we smoothly found potent PROTACs effectively inhibit triple‐negative breast cancer (TNBC) cell growth and induce rapid, selective targeted degradation of cyclin‐dependent kinase 9 (CDK9). The study introduces a versatile platform for assembling PROTACs on plates, followed by direct biological evaluation. This approach provides a promising opportunity for high‐throughput synthesis of PROTAC libraries, thereby enhancing the efficiency of exploring chemical space and accelerating the discovery of PROTACs.