Sharma, IndrajeetBain, Anae2022-06-212022-06-212022-08-04https://hdl.handle.net/11244/335873Within the realm of drug discovery more intricate, rigid small molecules exhibit higher potencies as drug leads and candidates. This is because molecules with three-dimensional features such as stereochemistry and bond saturation have increased binding specificities, decreased toxicological liabilities, and favorable pharmacological properties. Natural products, due to their structural complexity, have historically established the blueprint for drug discovery, inspiring the cores or complete scaffolds for most pharmaceuticals available today. As a result, over 50% of available drugs are either natural products or their derivatives. While natural products have historically served as trailblazers for the pharmaceutical industry, in the past twenty years drug-discovery programs have de-emphasized natural products in favor of high-throughput screening of synthetic chemical libraries. This shift has been met with diminishing returns, as these changes have led to an average ‘hit rate’ of >0.001% for pharmaceutical screenings of synthetic chemical libraries. Resultantly, there has been a resurgence in the belief that natural product-based drug design is the most practical model for future drug discovery efforts. Therefore, there is a need for convergent methods to access complex cores to sustain these early discovery programs, as often trivial differences in substrates lead to vast differences in site-binding and drug efficacy. There are several challenges associated with natural product-based drug design, however, the most glaring is the lack of low-cost, efficient methodologies to access privileged natural product-like cores. This dissertation addresses these issues with two primary foci: 1. The implementation of carbenoid-initiated reactions to form complex, natural product-like cores in efficient transformations; and 2. the utilization of metal catalysts for highly specific transformations. While my preliminary studies feature precious metal catalysts, the continuation of my research features Earth-abundant catalysts. These focuses have converged for the development of methodologies surrounding two small-molecule frameworks: spirocycles and carbohydrates. Through the implementation of metal-carbenoids, we have developed stereoselective protocols to access these privileged frameworks readily in tandem or cascade strategies. Cascade reactions are multiple synthetic transformations that can occur in a single reaction pot, thereby truncating long reaction sequences into a single step. These reactions reduce the number of overall steps necessary to synthesize the desired compound while facilitating the rapid generation of structural complexity from simple starting materials. Likewise, multiple reactions can be completed in a single flask, which negates the need for the isolation of intermediates, thereby reducing the total cost of synthesis. The work herein details cascade sequences that can be utilized to access both scaffolds.Attribution-NonCommercial-ShareAlike 4.0 InternationalOrganic ChemistryMetal CarbenoidGlycosylationSpirocyclization