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Showing 1 to 16 of 16 for “"C-H borylation"”.
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Bipyridine Ligands for use in Polymer-Supported Iridium Catalyzed C-H Borylation
… precatalyst afford a highly efficient C-H borylation, but studies of polymer-supported bipyridine ligands have not been extensively researched. With an aim to exploring this approach to allow recycling of the expensive iridium catalysts synthesis of new bipyridine ligands were undertaken. A …
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Application of Iridium-Catalysed C–H Borylation to the Functionalisation of Indoles
… novel applications of the iridium-catalysed C–H borylation of indoles. Research commenced with the development of a general procedure for the conversion of indoles 242 to 7-hydroxyindoles 245 and indolequinones 243. This was achieved by a three-step procedure – an initial C7–H borylation was …
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An Exploration of Ion Pairing Interactions as a Tool to Control Regioselectivity in Iridium-Catalysed C–H Borylation
… and para selectivity in iridium catalysed C–H borylation. An ion pairing interaction between a functionalised ligand and matching functionality on a substrate was initially explored for achieving meta C–H selectivity. By using an anionic sulfonate group on the ligand and cationic quaternary …
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The Application of Catalysis based on Hydrogen Bonding and Ion-pairing Interactions to Asymmetric Minisci-type Alkylations of Azines and Iridium-Catalysed C-H Borylation.
… to meta-selective iridium-catalysed C-H borylation. Although there are a several reports of enantioselective ortho-selective borylation of arenes, a reaction that reached more remote positions had not yet been realised. The association of a chiral countercation with an anionic sulfonated …
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Developing and Understanding Iridium-Catalysed Arene Borylation
Iridium catalysed C-H borylation has moved from an interesting observation to an efficient catalytic reaction. This work has developed and improved upon some of the key issues associated with the methodology. The one-pot conversion of aryl boronates, generated by C-H borylation, to other …
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New methodologies and approaches to reaction discovery in transition metal catalysis
… have been developed based upon iridium-catalyzed borylation of aromatic and heteroaromatic C-H bonds. A general, one-pot method for alkylation of arenes with the site-selectivity controlled by steric effects as opposed to electronic effects via Ir-catalyzed C-H borylation followed by Pd- or …
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Development of Improved Methodologies Toward the Formation of C-C and C-N Bonds
… areas have been studied: C-N bond formation, C-H borylation, and silylvinylation of alkynes. </p> <p>In Chapter 1, palladium-catalyzed amidation has been used to effectively form C-N bonds toward the synthesis of valuable imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines. The reaction conditions …
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CATALYTIC BORYLATION OF C-H BONDS: A ROUTE TO PHOTOPHYSICALLY INTERESTING PYRENE DERIVATIVES
… properties. Using the regiospecific direct C-H borylation of pyrene with an Ir-based catalyst, prepared in situ via reaction of [Ir(OMe)COD]2 with 4,4’-di-tert-butyl-2,2’-bipyridine, 2,7-bis(Bpin)pyrene 1 and 2-(Bpin)pyrene 2 (pin = OCMe2CMe2O) were synthesized. Straightforward derivatization …
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Iridium-catalyzed borylation of aromatic and aliphatic C-H bonds: methodology and mechanism
… cyanation of arenes by iridium-catalyzed C-H borylation and copper-mediated cyanation of the resulting arylboronate esters is described in Chapter 2. This process relies on a previously unknown method to conduct the cyanation of arylboronic esters, and conditions for this new transformation …
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Synthetic Retinoids
… forming reactions and transition metal-catalysed borylation of aromatic and vinylic C-H bonds, respectively. Chapter two details the application of sequential Ir-catalysed aromatic C-H borylations, Pd-catalysed C-C bond forming reactions and Rh-catalysed vinylic C-H borylations for the …
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A hydrogen bonding ortho-directing effect for the iridium catalyzed borylation of NH(t-BOC) aromatics
The C-H borylation of aromatic substrates has evolved from a stoichiometric curiosity to a valuable methodology for the synthetic chemist. Understandings of regioselective activation and high functional group tolerance have been considerably praised. Most aromatic substituents, such as alkyl, …
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Carbon-carbon bond formation methods for the preparation of shape-persistent architectures
… three methodologies: iridium-catalyzed arene C-H borylation; zinc- mediated alkynylations; and Lewis acid promoted Mo nitride-alkyne metathesis, are presented as improvements for the preparation of carbon-rich architectures. In addition, X-ray crystallographic analysis of two classes of compounds …
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Planning And Interpretation Of Late Stage Functionalisation Reactions
… approach for predicting selectivity of C–H borylation using a multi-task language model. We show it is possible to predict the borylation product with accuracy comparable to that of a synthetic chemistry expert. We compare performance of our language model with a graph neural network, …
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Studies in iridium and manganese catalysis in C-H activation and reductive transformations
… motifs. In particular, iridium-catalysed C−H borylation has proven a useful means of heteroarene functionalisation, due to its ability to produce highly versatile aryl organoboronate intermediates. The quinoline nucleus is a ubiquitous, strategic target, given its role as a key scaffold in a …
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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
… 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 metalloporphyrins. Porphyrins are a privileged class of ligand that are challenging to render chiral. In this work, we …
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Development of Ion Pairing Strategies that Utilise Cations to Control Selectivity in Transition Metal-Catalysed Functionalisation of C–H Bonds
… Chapter 2 focusses on the iridium-catalysed borylation of aromatic C(sp2)–H bonds. The lack of regiocontrol for 1,2-disubstituted arenes under standard conditions has previously been addressed by introducing an ion pairing interaction between a cationic substrate and an anionic ligand to …