Ruthenium-catalysed C‒H amidation for the late-stage synthesis of PROTACs

PROteolysis TArgeting Chimeras (PROTACs) are a powerful modality in drug discovery, offering the potential to address outstanding medical challenges. However, the synthetic feasibility of PROTACs, and the empiric and complex nature of their structure-activity relationships continue to present formidable limitations. As such, modular and reliable approaches to streamline the synthesis of these compounds are highly desirable. Here, we describe a robust ruthenium-catalysed late-stage C‒H amidation strategy, to provide modular access to both fully elaborated PROTACs and drug conjugates. Using readily available dioxazolone reagents, a broad range of inherently present functional groups can guide the C–H amidation on complex bioactive molecules. High selectivity and functional group tolerance enable the late-stage installation of linkers bearing orthogonal functional handles for downstream elaboration. Finally, the single-step synthesis of PROTAC and biotin conjugates is demonstrated, showcasing the potential of this methodology to provide efficient and sustainable access to advanced therapeutics and chemical biology tools.