Radical-mediated transformations of carbohydrates enabled by photoredox and hydrogen atom transfer
Julia Turner
Postdoctoral Fellow, Department of Chemistry
University of Utah
Monday, November 4, 2024
11 a.m.
Hybrid: C2-361 and Teams
Abstract: A significant portion of therapeutics are derived from natural products, many of which contain sites of glycosylation. The carbohydrate moieties found in these natural products, often referred to as rare sugars due to their relatively low natural abundance, display various modifications when compared to more abundant carbohydrates, such as glucose or galactose. Photoredox and hydrogen atom transfer (HAT) co-catalysis has recently enabled the development of radical-mediated transformations of common carbohydrates into structurally diverse carbohydrate moieties. The work described in this thesis details the use of photoredox/HAT co-catalysis for the synthesis of rare carbohydrates from readily accessible monoacylated pyranoside precursors. Mechanistic studies and the application of the developed method towards the synthesis of a rare sugar oligosaccharide fragment are also presented. Additionally, computational studies provide an understanding of the fundamental effects (stereochemical configuration, conformation, substitution pattern, noncovalent interactions) that govern the site-selectivity of photoredox/HAT co-catalytic reactions and the stability of the resulting radicals.