“…Drug discovery is an expensive and risky enterprise where large investments and low drug approval rates heavily incentivise innovation in chemical synthesis that can streamline discovery and manufacture. , LSF is now a key strategy used to advance medicinal chemistry programs, enabling substantial opportunities for efficiently accessing a diverse range of analogues of existing biologically active molecules. , The fundamental benefit of this approach is the avoidance of time- and resource-intensive de novo synthesis of individual analogues. The primary applications of LSF in drug discovery programs have been comprehensively reviewed elsewhere. ,− ,− Of these, the most common application is to generate diverse libraries from existing drug molecules or natural products that explore novel chemical space to probe SAR − (e.g., sclareolide ( 1 ), Figure A). In addition, LSF methodologies have also been used in the preparation of radiolabeled chemical probes (Figure B), which play a vital role in studying metabolic pathways, establishing putative mechanisms of action and quantifying target engagement in vivo . − Finally, LSF has been used in the identification and preparation of drug metabolites (Figure C)a crucial aspect of drug discovery to develop an improved understanding of these pathways en route to safety and efficacy studies. ,, …”