Abstract
Despite the proliferation of validated oncogenic targets, the translation of bioactive natural products and high-throughput screening hits into clinical candidates is frequently stalled by the "Synthesis Bottleneck"—the prohibitive cost and technical difficulty of optimizing complex chemical scaffolds. This literature-based review addresses this critical impasse by proposing a paradigm shift from rigid structure-replication to function-mimicry, exemplified by the evolution of the complex marine natural product Halichondrin B to the simplified clinical drug Eribulin. It presents a resource-stratified framework that empowers researchers across the funding spectrum to navigate synthetic intractability. For resource-constrained academic laboratories, it highlights the emergence and revolution of ultra-large "make-on-demand" virtual libraries and pharmacophore hopping. For mid-tier biotechnology firms, it explores fragment-based drug discovery and free energy perturbation modeling to de-risk synthesis. For well-resourced pharmaceutical entities, it discusses the closed-loop integration of generative AI with autonomous robotic synthesis. Finally, it examines modality switching—specifically Proteolysis-Targeting Chimeras (PROTACs) and covalent inhibitors—as a strategic "escape hatch" for targets that remain refractory to traditional small-molecule optimization. By matching specific computational and experimental tools to available resources, this framework aims to democratize the discovery of developable cancer therapies and rescue promising biological hypotheses from the graveyard of intractable chemistry.