Natural product-inspired drug design is a key and time-tested strategy in the development of new medicines. Nature produces an astounding number of highly complex molecules, each of which has specific functions important for the survival of the producing species. As function follows from structure, the various substructures found in the small molecules produced by living organisms (so-called metabolites) are important leads in the molecular design of possible new medicines. However, many of the conserved but essential structural patterns in metabolites are stereochemically complex and can pose a considerable synthetic challenge. In particular, five-membered carbon rings are ubiquitous substructures in many metabolites, but there are few general methods that allow their controlled assembly from simple chemical building blocks. This research proposal will focus on a recently discovered sulfur-heterocyclic reagent and its remarkable ability to swiftly form a five-membered ring with simple alkene substrates. Thus, a path is outlined for the development of new synthetic methods that allow the rapid production of cyclopentanoid scaffolds from a wide range of starting materials. To increase the strategic potential of this synthetic work, at least two specific target classes will be envisaged: (1) indole and indoline-based drug scaffolds, and (2) carbanucleoside analogues. Both of these compound classes are highly relevant for multiple therapeutic areas in modern drug discovery.