A5055043024- Electrochemical Analysis and Applications
- Electrocatalysts for Energy Conversion
- Radical Photochemical Reactions
- CO2 Reduction Techniques and Catalysts
- Asymmetric Synthesis and Catalysis
- Fluorine in Organic Chemistry
- Organoboron and organosilicon chemistry
- Catalytic C–H Functionalization Methods
- Axial and Atropisomeric Chirality Synthesis
- Molecular spectroscopy and chirality
- Oxidative Organic Chemistry Reactions
- Catalytic Cross-Coupling Reactions
- X-ray Diffraction in Crystallography
- Analytical Chemistry and Chromatography
- HIV-related health complications and treatments
- Sulfur-Based Synthesis Techniques
- HIV Research and Treatment
- Inorganic Fluorides and Related Compounds
- Synthetic Organic Chemistry Methods
- Music History and Culture
- Crystallization and Solubility Studies
- Advanced Chemical Sensor Technologies
- Advanced battery technologies research
- Catalysis and Oxidation Reactions
- Synthesis and Catalytic Reactions
Dartmouth College
2022
Groote Schuur Hospital
2022
University of Utah
2019-2021
Salt Lake Regional Medical Center
2019-2021
University of Bristol
2015-2017
At Bristol
2017
University of Oxford
2015-2016
Royal Navy
1953
The formation of highly enantioenriched boronic esters through both stoichiometric and catalytic methods has received much attention over the past decade. Accordingly, transformations ester moiety into other functional groups is considerable interest in synthesis. Specifically, which retain high enantioenrichment starting ester, either a stereoretentive or stereoinvertive pathway, lead to new C-C, C-O, C-N, C-X, C-H bonds at stereogenic centres. This feature article summarises current state...
Vinyl boronates react with electron-deficient alkyl iodides in the presence of visible light to give boronic esters which two new C–C bonds have been created. The reaction occurs by radical addition an vinyl boronate followed electron transfer another molecule iodide, continuing chain, and triggering a 1,2-metalate rearrangement. In number cases, use photoredox catalyst enhances yields significantly. scope precursor includes α-iodo ketones, esters, nitriles, primary amides, α-fluorinated...
The highly enantioselective sulfa-Michael addition of alkyl thiols to unactivated α-substituted acrylate esters catalyzed by a bifunctional iminophosphorane organocatalyst under mild conditions is described. strong Brønsted basicity the moiety catalyst provides necessary activation thiol pro-nucleophile, while two tert-leucine residues flanking central thiourea hydrogen-bond donor facilitate high enantiofacial selectivity in protonation transient enolate intermediate. reaction broad scope...
The enantiospecific conversion of chiral secondary boronic esters into alkylfluorides is reported. Boronate complexes derived from and PhLi were used as nucleophiles, with Selectfluor II the electrophilic fluorinating agent, to afford in short reaction times. addition styrene a radical trap was found enhance enantiospecificity. A broad range alkyl converted almost complete enantiospecificity by this method.
Cobalt complexes have shown great promise as electrocatalysts in applications ranging from hydrogen evolution to C–H functionalization. However, the use of such often requires polydentate, bulky ligands stabilize catalytically active Co(I) oxidation state deleterious disproportionation reactions enable desired reactivity. Herein, we describe bidentate electronically asymmetric an alternative approach stabilizing transient species. Using rates electrochemically generated a model for...
The oxidative addition of organic electrophiles into electrochemically generated Co(I) complexes has been widely utilized as a strategy to produce carbon-centered radicals when cobalt is ligated by polydentate ligand. Changing bidentate ligand provides the opportunity access discrete Co(III)-C bonded for alternative reactivity, but knowledge how and/or substrate structures affect catalytic steps pivotal reaction design and catalyst optimization. In this vein, experimental studies that can...
Allylboronic esters react readily with carbonyls and imines (π-electrophiles), but are unreactive toward a range of other electrophiles. By addition an aryllithium, the corresponding allylboronate complexes display enhanced nucleophilicity, enabling to electrophiles (tropylium, benzodithiolylium, activated pyridines, Eschenmoser's salt, Togni's reagent, Selectfluor, diisopropyl azodicarboxylate (DIAD), MeSX) in high regio- stereocontrol. This protocol provides access key new functionalities,...
Abstract In the presence of trifluoromethylsulfonium reagents, boronate complexes derived from 2‐lithio furan and non‐racemic secondary tertiary alkyl or aryl boronic esters undergo deborylative three‐component coupling to give corresponding 2,5‐disubstituted furans with excellent levels enantiospecificity. The process proceeds via reaction a trifluoromethyl radical, which triggers 1,2‐metallate rearrangement upon single‐electron oxidation. Alternative electrophiles can also be used in place...
A conjunctive functionalization process enables a diastereoselective three-component coupling of vinyl boronate complexes with range electrophiles.
The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination palladium and chiral phosphoric acid was investigated combined experimental statistical modeling approach. Experiments to probe nonlinear effects, the reactivity deuterium-labeled substrates, control experiments revealed that nucleophilic attack π-allylpalladium intermediate is enantio-determining step, which phosphate anion involved stereoinduction. Using...
In the presence of trifluoromethylsulfonium reagents, boronate complexes derived from 2-lithio furan and non-racemic secondary tertiary alkyl or aryl boronic esters undergo deborylative three-component coupling to give corresponding 2,5-disubstituted furans with excellent levels enantiospecificity. The process proceeds via reaction a trifluoromethyl radical, which triggers 1,2-metallate rearrangement upon single-electron oxidation. Alternative electrophiles can also be used in place reagents...
Through kinetic studies combining electroanalytical techniques with multivariable linear-regression (MLR) analysis, a pattern recognition platform is established to determine the electron-transfer mechanism (inner-sphere or outer-sphere) of an electrochemical reduction benzyl bromides, mediated by different cobalt complexes.
Abstract Bipyridine complexes of Ni are used as catalysts in a variety reductive transformations. Here, the electroreduction [Ni(Mebpy) 3 ] 2+ (Mebpy=4,4′‐dimethyl‐2,2′‐bipyridine) dimethylformamide is reported, with aim determining redox mechanism and oxidation states products formed under well‐controlled electrochemical conditions. Results from cyclic voltammetry, steady‐state voltammetry (SSV) chronoamperometry demonstrate that undergoes two sequential 1 e reductions at closely separated...
Abstract The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination palladium and chiral phosphoric acid was investigated combined experimental statistical modeling approach. Experiments to probe nonlinear effects, the reactivity deuterium‐labeled substrates, control experiments revealed that nucleophilic attack π‐allylpalladium intermediate is enantio‐determining step, which phosphate anion involved stereoinduction. Using...
The asymmetric induction afforded by a chiral sulfinyl group in palladium/Brønsted-acid-catalyzed intramolecular allylic amination was investigated. Predictions of the diastereoselectivity for various substrates under assumed total thermodynamic control were obtained from density functional theory (DFT), and correlation with experimental data demonstrates abrupt changes to kinetic across substrate scope. resulting heterocyclic product readily converted valuable isoindoline-1-carboxylic acid...
Bipyridine complexes of Ni are used as catalysts in a variety reductive transformations. Here, the electroreduction [Ni(Mebpy) 3 ] 2+ (Mebpy = 4,4’-dimethyl-2,2’-bipyridine) dimethylformamide is reported, with aim determining redox mechanism and oxidation states products formed under well-controlled electrochemical conditions. Results from cyclic voltammetry, steady-state voltammetry (SSV) chronoamperometry demonstrate that undergoes two sequential 1 e reductions at closely separated...
Redox catalysis has been broadly utilized in electrochemical synthesis due to its kinetic advantages over direct electrolysis. The appropriate choice of redox mediator can avoid electrode passivation and overpotential, which strongly inhibit the efficient activation substrates Despite benefits brought by catalysis, establishing precise nature substrate remains challenging. Herein, we determine that a Co(I) complex bearing two...
<p>Bipyridine complexes of Ni are used as catalysts in a variety reductive transformations. Here, the electroreduction [Ni(Mebpy)<sub>3</sub>]<sup>2+</sup> (Mebpy = 4,4’-dimethyl-2,2’-bipyridine) dimethylformamide is reported, with aim determining redox mechanism and oxidation states products formed under well-controlled electrochemical conditions. Results from cyclic voltammetry, steady-state voltammetry (SSV) chronoamperometry demonstrate that undergoes two...
Abstract A variety of chiral β‐mercaptoesters such as (III), (V), and (VII) is prepared by BIMP‐catalyzed enantioselective sulfa‐Michael addition alkyl thiols (II) to acrylate esters.
Abstract Boronates, generated in situ from chiral secondary boronic esters and phenyllithium, are enantiospecifically transformed into alkylfluorides by reaction with selectfluor II (SF2) the presence of styrene as a radical trap.
THEhospital consultants, as their advice, when sought, is usually studded with proprietary preparations.Very often, if the patient has been in hospital, he presents himself at surgery a detailed list of things to be given.We have yet hear consultant having justify his prescribing.Until such time Minister courage tackle service whole-patients, G.P.s, chemists, and drug manufacturers-we consider un- likely achieve reduction bill we all wish see.-We are, etc.,