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Showing 1 to 13 of 13 for “"Cinchona alkaloids"”.
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Harnessing cheminformatics for catalyst design I. Investigation into a general, asymmetric synthesis of cinchona alkaloid analogs towards asymmetric phase transfer II. Development of an enantioselective brønsted acid catalyzed four-component Ugi reaction
… ‘core’ catalyst scaffolds were chosen. First, Cinchona alkaloids were studied against an asymmetric phase transfer catalyzed cyclopropanation reaction. Second, (R)-BINOL derived phosphoric acids were studied in regards to the brønsted acid catalyzed Ugi reaction. In regards to Cinchona …
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Utilising Non-Covalent Interactions in Developing Enantioselective Radical Transformations
… ion-paired to a chiral cation derived from cinchona alkaloids, to create a chiral environment around the metal centre. The challenges encountered for both approaches are discussed. The third research chapter describes the incipient phase of a project based on the use of cinchona …
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The Design and Application of Ion-paired Ligands to Address Selectivity Challenges in Transition Metal Catalysed Oxygen and Nitrogen Transfer Reactions
… to chiral cations based on readily available cinchona alkaloids and have been shown to induce enantioselectivity in challenging reaction types: iridium- catalysed C-H borylation, and rhodium-catalysed C-H amination and alkene aziridination. Chapter 2 explores the synthesis of novel ion-paired …
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Insights into the mechanism of action of quinoline antimalarials against Plasmodium falciparum revealed by novel fluorescent analogues and chemical proteomics
… methanols, represented by the diastereomeric Cinchona alkaloids quinine and quinidine, and the 4-aminoquinolines, represented by chloroquine. Mechanistic studies of these antimalarials have typically focused on the inhibition of haemozoin biocrystallisation within the acidic digestive vacuole …
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The preparation and characterization of diastereomeric (+)-quinicinol
… (I) (see Fig. 1) (obtained from the bark of the Cinchona tree) is still listed among the most effective (1, 3, 4). Consequently, there has been much study done on isomers and derivatives of quinine, where the vinyl group on C-3, various substituents or, and the stereochemistry of, C-9, and C-8 to …
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New Catalysts for Asymmetric Nitrene Transfer Based on Ion-Pairing Between Sulfonated Rhodium(II,II) Tetracarboxylates and Chiral Cations: Design, Synthesis and Applications to Enantioselective Carbon-Nitrogen Bond Formation
… with two chiral cations based on quaternised cinchona alkaloids. The modular catalyst design is used to construct a large library with the aim of exerting catalyst-control over selectivity in the ensuing nitrene-transfer reactions. In the second part, proof of concept using these dimers is …
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Investigations of Catalysts Which Utilise Non-Covalent Interactions to Control Enantioselectivity in Rhodium-Catalysed Amination of C(sp3)–H Bonds
… rhodium(II) dimers ion-paired with N-quaternised Cinchona alkaloids are described herein. Design and initial synthesis of these novel catalysts was performed prior by Dr. Alex Fanourakis, and their application towards substrate-directed amination of aryl alcohols via a key alcohol-sulfonate …
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Phase transfer catalysis: catalyst screening, reaction development, and mechanism analysis
… a small library of catalysts derived from Cinchona alkaloids was examined for selectivity and activity. An array of substituent modifications were tested, examining the role of steric and electronics on catalyst activity. Catalysts that contained large substituents attached to the …
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Controlling the Regio- and Enantioselectivity of Iridium-Catalysed Arene Borylation Using Sulfonated Bipyridine Ligands
… cation, derived from the privileged class of cinchona alkaloids, is associated with an anionic sulfonated bipyridine ligand through ion-pairing. This chiral ligand enables a long-range, desymmetrising arene borylation to occur, forming new carbon or phosphorus stereocentres with high levels of …
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CONSTRUCTING CHIRAL CENTRES VIA O→C ARYL AND ACYL MIGRATIONS: EXPLORING REACTION POTENTIAL
… of phase transfer catalysts, based on cinchona alkaloids, for the induction of chirality in ketone-based precursors. Further discussion continues with the synthesis of amide-based substrates from lactones and amines, and the use of C2-symmetric chiral auxiliaries to induce chirality …
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Organocatalytic asymmetric mannich-type reactions: an easy approach to optically active amine derivatives
… protocols for Mannich-type reactions mediated by Cinchona alkaloids derivatives (Scheme I, left); the second topic, instead, regards the study of a new approach towards the enantioselective total synthesis of Aspirochlorine, a potent gliotoxin that recent studies indicate as a highly selective and …