The Development of Transition Metal Catalyzed Reactions for Applications in Complex Molecule Synthesis, Methodological Development and Biomass Processing.

[摘要] Described herein are four projects: Chapter 1 will discuss the development of an intermolecular C–H functionalization of indoles with diethyl bromomalonate mediated by the photoredox catalyst, Ru(bpy)3Cl2.The direct functionalization of indoles is of interest to the greater synthetic community due to their ubiquity within the natural world. The difficulty in developing an intermolecular radical alkylation reaction is principally due to competitive side reactions such as reductive dehalogenation. Our approach enables a room temperature alkylation of a wide variety of electron rich heterocycles that is high-yielding, scalable and functional group tolerant. Chapter 2 will describe the development of an unusual vicinal olefin difunctionalization reaction using high-valent palladium catalysis for the synthesis of highly functionalized spirocyclohexadienones and polycyclic aromatic compounds. This synthetic approach has applications in the total synthesis of the antibiotic platensimysin.It will also provide commentary on the differences in reactivity between conventional PdII/0 alkene difunctionalization and ones that are mediated by higher oxidation states of palladium. Chapter 3 will present the application of visible light photoredox catalysis towards the degradation of lignin.Lignin is the second most abundant biopolymer on earth and is the only renewable feedstock for aromatic compounds.However, there are no currently implemented technologies that exploit this resource for the purpose of producing renewable fine chemicals.This chapter will discuss our lab’s first successes in the validation of this concept.Specifically, in the development of a two-stage, chemoselective benzylic alcohol oxidation/photocatalytic reductive C–O bond cleavage reaction. The final chapter will discuss a collaborative project between the Stephenson group and the Pratt group concerning a scalable biomimetic total synthesis of the resveratrol dimers quadrangularin A and pallidol.The beneficial properties of resveratrol are often attributed to its purported ability to act as a radical trapping antioxidant and maintain redox homeostasis within the body. As a result of our synthesis, we wereable to provide sufficient material for the rigorous evaluation of its antioxidant activity and challenge this hypothesis.

[发布机构] University of Michigan

[效力级别] Resveratrol Natural Products

[关键词] Photoredox Catalysis;Resveratrol Natural Products;Total Synthesis;Lignin;Biomass Processing;High Valent Palladium Catalysis;Chemistry;Science;Chemistry