Publications
55 results found
Yang X, Kuziola J, Béland VA, et al., 2023, Bismuth-Catalyzed Amide Reduction., Angew Chem Int Ed Engl, Vol: 62
In this article we report that a cationic version of Akiba's BiIII complex catalyzes the reduction of amides to amines using silane as hydride donor. The catalytic system features low catalyst loadings and mild conditions, en route to secondary and tertiary aryl- and alkylamines. The system tolerates functional groups such as alkene, ester, nitrile, furan and thiophene. Kinetic studies on the reaction mechanism result in the identification of a reaction network with an important product inhibition that is in agreement with the experimental reaction profiles.
Yang X, Kuziola J, Béland VA, et al., 2023, Bismuth‐Catalyzed Amide Reduction, Angewandte Chemie, Vol: 135, ISSN: 0044-8249
<jats:title>Abstract</jats:title><jats:p>In this article we report that a cationic version of Akiba's Bi<jats:sup>III</jats:sup> complex catalyzes the reduction of amides to amines using silane as hydride donor. The catalytic system features low catalyst loadings and mild conditions, en route to secondary and tertiary aryl‐ and alkylamines. The system tolerates functional groups such as alkene, ester, nitrile, furan and thiophene. Kinetic studies on the reaction mechanism result in the identification of a reaction network with an important product inhibition that is in agreement with the experimental reaction profiles.</jats:p>
Bures J, Larrosa I, 2023, Organic reaction mechanism classification using machine learning, NATURE, Vol: 613, Pages: 689-+, ISSN: 0028-0836
Burés J, Armstrong A, Blackmond DG, 2023, A Tutorial on <scp>Kinetic‐Assisted</scp> Mechanistic Analysis in Asymmetric Aminocatalysis, Publisher: Wiley
Alamillo-Ferrer C, Hutchinson G, Bures J, 2022, Mechanistic interpretation of orders in catalyst greater than one, NATURE REVIEWS CHEMISTRY, Vol: 7, Pages: 26-34
Dumon AS, Rzepa HS, Alamillo-Ferrer C, et al., 2022, A computational tool to accurately and quickly predict F-19 NMR chemical shifts of molecules with fluorine-carbon and fluorine-boron bonds, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 24, Pages: 20409-20425, ISSN: 1463-9076
Hutchinson G, Alamillo-Ferrer C, Fernandez-Pascual M, et al., 2022, Organocatalytic Enantioselective alpha-Bromination of Aldehydes with N-Bromosuccinimide, JOURNAL OF ORGANIC CHEMISTRY, Vol: 87, Pages: 7968-7974, ISSN: 0022-3263
- Author Web Link
- Cite
- Citations: 1
Ali C, Blackmond DG, Bures J, 2022, Kinetic Rationalization of Nonlinear Effects in Asymmetric Catalytic Cascade Reactions under Curtin-Hammett Conditions, ACS CATALYSIS, Vol: 12, Pages: 5776-5785, ISSN: 2155-5435
Bures J, Armstrong A, Blackmond D, 2021, Downstream Paradigm in Enamine Catalysis: Comment on “On Stereocontrol in Organocatalytic α-Chlorinations of Aldehydes”
<jats:p><p>We present kinetic modeling results in order to evaluate different mechanistic proposals that have been presented concerning the role of “downstream intermediates” in enamine catalysis. The focus of the debate is the identity and role of aminal intermediates. Are the aminals <i>syn</i> or are they <i>anti</i>, or are both observed? Do they lie on the catalytic cycle, as we suggest, or are they off-cycle species?</p></jats:p>
Bures J, Armstrong A, Blackmond D, 2021, Downstream Paradigm in Enamine Catalysis: Comment on “On Stereocontrol in Organocatalytic α-Chlorinations of Aldehydes”
<jats:p>We present kinetic modeling results in order to evaluate different mechanistic proposals that have been presented concerning the role of “downstream intermediates” in enamine catalysis. The focus of the debate is the identity and role of aminal intermediates. Are the aminals <jats:italic>syn</jats:italic> or are they <jats:italic>anti</jats:italic>, or are both observed? Do they lie on the catalytic cycle, as we suggest, or are they off-cycle species?</jats:p>
Hutchinson G, Alamillo-Ferrer C, Bures J, 2021, Mechanistically Guided Design of an Efficient and Enantioselective Aminocatalytic alpha-Chlorination of Aldehydes, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 143, Pages: 6805-6809, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 10
Gesslbauer S, Hutchinson G, White A, et al., 2021, Chirality-Induced catalyst aggregation: insights into catalyst speciation and activity using chiral aluminum catalysts in cyclic ester ring-opening polymerization, ACS Catalysis, Vol: 11, Pages: 4084-4093, ISSN: 2155-5435
A series of chiral-at-metal aluminum complexes have been synthesized using chiral catam ligands. Reactivity studies demonstrate the importance of alkoxide bulkiness and complex chirality in inducing catalyst aggregation. This has been exploited in cyclic ester ring-opening polymerization (ROP). For ε-Cl ROP, enantiopure catalysts were found to outperform a racemic mixture of catalysts, as the racemic mixture resulted in lower activity heterodimeric catalytic species and reduced polymerization rates. In the case of L-LA, one catalyst enantiomer was found to be the most active of the series and outperformed both the other enantiomer and the corresponding achiral catalyst. Very high activities were observed and up to 9,200 equivalents of L-LA were polymerized in 4.5 min at 150 °C with TOF > 100,000 h–1 under industrially relevant conditions. Analysis of the catalyst orders for these reactions provided a meaningful catalyst speciation-activity relationship enabling improved understanding of both catalyst speciation and the activity of each catalytic species involved in cyclic ester ROP using chiral aluminum catalysts.
Alamillo-Ferrer C, Nielsen CD-T, Salzano A, et al., 2021, Understanding the Diastereopreference of Intermediates in Aminocatalysis: Application to the Chiral Resolution of Lactols, JOURNAL OF ORGANIC CHEMISTRY, Vol: 86, Pages: 4326-4335, ISSN: 0022-3263
Hutchinson G, Welsh CDM, Bures J, 2021, Use of Standard Addition to Quantify In Situ FTIR Reaction Data, JOURNAL OF ORGANIC CHEMISTRY, Vol: 86, Pages: 2012-2016, ISSN: 0022-3263
- Author Web Link
- Cite
- Citations: 6
Seppanen O, Aikonen S, Muuronen M, et al., 2020, Dual H-bond activation of NHC-Au(i)-Cl complexes with amide functionalized side-arms assisted by H-bond donor substrates or acid additives, CHEMICAL COMMUNICATIONS, Vol: 56, Pages: 14697-14700, ISSN: 1359-7345
- Author Web Link
- Cite
- Citations: 11
Somerville RJ, Hale LVA, Gomez-Bengoa E, et al., 2019, Intermediacy of Ni-Ni Species in sp(2) C-O Bond Cleavage of Aryl Esters: Relevance in Catalytic C-Si Bond Formation (vol 140, pg 8771, 2018), JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 141, Pages: 20565-20565, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 2
Nielsen CD-T, White AJP, Sale D, et al., 2019, Hydroarylation of Alkenes by Protonation/Friedel-Crafts Trapping: HFIP-Mediated Access to Per-aryl Quaternary Stereocenters, JOURNAL OF ORGANIC CHEMISTRY, Vol: 84, Pages: 14965-14973, ISSN: 0022-3263
Pericas M, Gutian E, Angeles Monge M, et al., 2019, Real Sociedad Espanola de Quimica Awards 2019, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 58, Pages: 13625-13626, ISSN: 1433-7851
MartínezCarrión A, Howlett MG, AlamilloFerrer C, et al., 2019, Kinetic Treatments for Catalyst Activation and Deactivation Processes based on Variable Time Normalization Analysis, Angewandte Chemie, Vol: 131, Pages: 10295-10299, ISSN: 0044-8249
<jats:title>Abstract</jats:title><jats:p>Progress reaction profiles are affected by both catalyst activation and deactivation processes occurring alongside the main reaction. These processes complicate the kinetic analysis of reactions, often directing researchers toward incorrect conclusions. We report the application of two kinetic treatments, based on variable time normalization analysis, to reactions involving catalyst activation and deactivation processes. The first kinetic treatment allows the removal of induction periods or the effect of rate perturbations associated with catalyst deactivation from kinetic profiles when the quantity of active catalyst can be measured. The second treatment allows the estimation of the activation or deactivation profile of the catalyst when the order of the reactants for the main reaction is known. Both treatments facilitate kinetic analysis of reactions suffering catalyst activation or deactivation processes.</jats:p>
Martinez-Carrion A, Howlett MG, Alamillo-Ferrer C, et al., 2019, Kinetic Treatments for Catalyst Activation and Deactivation Processes based on Variable Time Normalization Analysis, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 58, Pages: 10189-10193, ISSN: 1433-7851
- Author Web Link
- Cite
- Citations: 27
Nielsen C, White AJP, Sale D, et al., 2019, Hydroarylation of Alkenes by protonation/Friedel-Crafts Trapping – HFIP-Mediated Access to Per-Aryl Quaternary Stereocentres, ChemRxiv
<jats:p><div><p>Upon treatment with a combination of HFIPand a strong Brønsted acid, alkenes behave as Brønsted bases and protonate to givecarbocations which can be trapped by electron rich arenes. The reaction constitutesa Friedel-Crafts (FC) hydroarylation which proceeds with Markovnikovselectivity and is orthogonal to traditional metal catalyzed processes. Theproducts contain polyarylated quaternary carbon atoms which are difficult toobtain <i>via</i> alternative methods. Intermoleculartransfer hydrogenation andhydrothiolation are also demonstrated. </p></div></jats:p>
Nielsen C, White A, Sale D, et al., 2019, Hydroarylation of Alkenes by protonation/Friedel-Crafts Trapping – HFIP-Mediated Access to Per-Aryl Quaternary Stereocentres, ChemRxiv
<div> <p>Upon treatment with a combination of HFIP and a strong Brønsted acid, alkenes behave as Brønsted bases and protonate to give carbocations which can be trapped by electron rich arenes. The reaction constitutes a Friedel-Crafts (FC) hydroarylation which proceeds with Markovnikov selectivity and is orthogonal to traditional metal catalyzed processes. The products contain polyarylated quaternary carbon atoms which are difficult to obtain <i>via</i> alternative methods. Intermolecular transfer hydrogenation and hydrothiolation are also demonstrated. </p> </div>
Nielsen CD-T, Bures J, 2019, Visual kinetic analysis, Chemical Science, Vol: 10, Pages: 348-353, ISSN: 2041-6520
Visual kinetic analyses extract meaningful mechanistic information from experimental data using the naked-eye comparison of appropriately modified progress reaction profiles. Basic kinetic information is obtained easily and quickly from just a few experiments. Therefore, these methods are valuable tools for all chemists working in process chemistry, synthesis or catalysis with an interest in mechanistic studies. This minireview describes the visual kinetic analyses developed in the last fifteen years and provides answers to the most common queries of new users. Furthermore, a video tutorial is attached detailing the implementation of both VTNA and RPKA.
Nielsen CD-T, Mooij WJ, Sale D, et al., 2019, Reversibility and reactivity in an acid catalyzed cyclocondensation to give furanochromanes - a reaction at the "oxonium-Prins' vs. "ortho-quinone methide cycloaddition' mechanistic nexus, Chemical Science, Vol: 10, Pages: 406-412, ISSN: 2041-6520
Herein we report a combined experimental and computational investigation of the acid catalyzed cyclocondensation reaction between styrenyl homoallylic alcohols and salicylaldehyde to form furanochromanes. We disclose a previously unreported isomerisation of the ‘unnatural’ trans-fused products to the diastereomeric ‘natural’ cis-fused congeners. Notwithstanding the appeal of assuming this corresponds to endo to exo isomerisation of Diels–Alder (D–A) adducts via concerted retro-cycloaddition/cycloaddition reactions of an in situ generated ortho-quinone methide with the styrenyl alkene, our combined Hammett/DFT study reveals a stepwise Prins-like process via discrete benzylic carbocation intermediates for all but the most electron deficient styrenes. As these reactions fortuitously lie at the intersection of these two mechanistic manifolds, it allows us to propose an experimentally determined indicative ρ+ value of ca. −3 as marking this nexus between a stepwise Prins-type pathway and a concerted cycloaddition reaction. This value should prove useful for categorising other reactions formally involving ‘ortho-quinomethides’, without the need for the extensive computation performed here. Logical optimisation of the reaction based upon the mechanistic insight led to the use of HFIP as an additive which enables exclusive formation of ‘natural’ cis-fused products with a ∼100-fold reaction rate increase and improved scope.
Somerville RJ, Hale LVA, Gomez-Bengoa E, et al., 2018, Intermediacy of Ni-Ni Species in sp(2) C-O Bond Cleavage of Aryl Esters: Relevance in Catalytic C-Si Bond Formation, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 140, Pages: 8771-8780, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 64
Aikonen S, Muuronen M, Wirtanen T, et al., 2018, Gold(I)-Catalyzed 1,3-O-Transposition of Ynones: Mechanism and Catalytic Acceleration with Electron-Rich Aldehydes, ACS CATALYSIS, Vol: 8, Pages: 960-967, ISSN: 2155-5435
- Author Web Link
- Cite
- Citations: 8
Colletto C, Bures J, Larrosa I, 2017, Reaction monitoring reveals poisoning mechanism of Pd-2(dba)(3) and guides catalyst selection, CHEMICAL COMMUNICATIONS, Vol: 53, Pages: 12890-12893, ISSN: 1359-7345
- Author Web Link
- Cite
- Citations: 6
Marais L, Bures J, Jordaan JHL, et al., 2017, A bis(pyridyl)-N-alkylamine/Cu(I) catalyst system for aerobic alcohol oxidation, ORGANIC & BIOMOLECULAR CHEMISTRY, Vol: 15, Pages: 6926-6933, ISSN: 1477-0520
- Author Web Link
- Cite
- Citations: 13
Companyo X, Bures J, 2017, Distribution of Catalytic Species as an Indicator To Overcome Reproducibility Problems, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 139, Pages: 8432-8435, ISSN: 0002-7863
- Author Web Link
- Cite
- Citations: 13
Bures J, 2017, What is the order of a reaction?, Topics in Catalysis, Vol: 60, Pages: 631-633, ISSN: 1022-5528
The order of a reaction in some species seems an obvious, trivial concept that all chemists master. However, in complex situations such as catalytic systems, the order of a reaction is not always that simple: it can be partial, negative and function of other parameters. In order to analyze rate laws and experimental orders of complex reaction networks, it is necessary to have a proper mathematical description of what the order of a reaction is. In general, chemists working in catalysis are unaware that such a mathematical description exists and therefore they are restricted to analyzing only extreme limit cases of rate laws. This manuscript offers a description and a simple demonstration of this concept, known as elasticity coefficient or normalized sensitivity. It also presents several examples of applications on classic and usual catalytic scenarios.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.