Imperial College London

DR JORDI BURES

Faculty of Natural SciencesDepartment of Chemistry

Visiting Researcher
 
 
 
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Contact

 

+44 (0)20 7594 2476j.bures

 
 
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Location

 

Fellows and Emeritus Suite Room 103a Upper LevelChemistrySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

37 results found

Seppänen O, Aikonen S, Muuronen M, Alamillo-Ferrer C, Burés J, Helaja Jet 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., Chem Commun (Camb)

Novel approach with amide-tethered H-bond donor NHC ligands enabled Au(i)-catalysis via H-bonding. The plain NHC-Au(i)-Cl complex catalysed conversions of terminal N-propynamides to oxazolines, and enyne cycloisomerization with an acid additive, in DCM at RT. DFT calculations enlightened the function of the side-arm in the activation.

Journal article

Somerville RJ, Hale LVA, Gomez-Bengoa E, Bures J, Martin Ret 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

Journal article

Nielsen CD-T, White AJP, Sale D, Bures J, Spivey ACet 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

Journal article

MartínezCarrión A, Howlett MG, AlamilloFerrer C, Clayton AD, Bourne RA, Codina A, VidalFerran A, Adams RW, Burés Jet 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

Journal article

Martinez-Carrion A, Howlett MG, Alamillo-Ferrer C, Clayton AD, Bourne RA, Codina A, Vidal-Ferran A, Adams RW, Bures Jet 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

Journal article

Nielsen C, White AJP, Sale D, Bures J, Spivey Aet al., 2019, Hydroarylation of Alkenes by protonation/Friedel-Crafts Trapping – HFIP-Mediated Access to Per-Aryl Quaternary Stereocentres

<jats:p>&lt;div&gt;&lt;p&gt;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 &lt;i&gt;via&lt;/i&gt; alternative methods. Intermoleculartransfer hydrogenation andhydrothiolation are also demonstrated. &lt;/p&gt;&lt;/div&gt;</jats:p>

Journal article

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.

Journal article

Nielsen CD-T, Mooij WJ, Sale D, Rzepa HS, Bures J, Spivey ACet 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.

Journal article

Somerville RJ, Hale LVA, Gomez-Bengoa E, Bures J, Martin Ret 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

Journal article

Aikonen S, Muuronen M, Wirtanen T, Heikkinen S, Musgreave J, Bures J, Helaja Jet 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

Journal article

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

Journal article

Marais L, Bures J, Jordaan JHL, Mapolie S, Swarts AJet 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

Journal article

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

Journal article

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.

Journal article

Burés J, 2016, Variable Time Normalization Analysis: General Graphical Elucidation of Reaction Orders from Concentration Profiles, Angewandte Chemie, Vol: 128, Pages: 16318-16321, ISSN: 0044-8249

Journal article

Bures J, 2016, Variable Time Normalization Analysis: General Graphical Elucidation of Reaction Orders from Concentration Profiles, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 55, Pages: 16084-16087, ISSN: 1433-7851

Journal article

Whitaker D, Burés J, Larrosa I, 2016, Ag(I)-catalyzed C-H activation: the role of the Ag(I) salt in Pd/Ag mediated C-H arylation of electron-deficient arenes, Journal of the American Chemical Society, Vol: 138, Pages: 8384-8387, ISSN: 0002-7863

The use of stoichiometric Ag(I)-salts as additives in Pd-catalyzed C–H functionalization reactions is widespread. It is commonly proposed that this additive acts as an oxidant or as a halide scavenger promoting Pd-catalyst turnover. We demonstrate that, contrary to current proposals, phosphine ligated Ag(I)-carboxylates can efficiently carry out C–H activation on electron-deficient arenes. We show through a combination of stoichiometric and kinetic studies that a (PPh3)Ag-carboxylate is responsible for the C–H activation step in the Pd-catalyzed arylation of Cr(CO)3-complexed fluorobenzene. Furthermore, the reaction rate is controlled by the rate of Ag(I)-C–H activation, leading to an order zero on the Pd-catalyst. H/D scrambling studies indicate that this Ag(I) complex can carry out C–H activation on a variety of aromatic compounds traditionally used in Pd/Ag-mediated C–H functionalization methodologies.

Journal article

Jimeno C, Günler ZI, Companyó X, Alfonso I, Bures J, Pericas MAet al., 2016, Deciphering the roles of multiple additives in organocatalyzed Michael additions, Chemical Communications, Vol: 52, Pages: 6821-6824, ISSN: 1364-548X

The synergistic effects of multiple additives (water and acetic acid) on the asymmetric Michael addition of acetone to nitrostyrene catalyzed by primary amine-thioureas (PAT) were precisely determined. Acetic acid facilitates hydrolysis of the imine intermediates, thus leading to catalytic behavior, and minimizes the formation of the double addition side product. In contrast, water slows down the reaction but minimizes catalyst deactivation, eventually leading to higher final yields.

Journal article

Burés J, 2016, A Simple Graphical Method to Determine the Order in Catalyst, Angewandte Chemie, Vol: 128, Pages: 2068-2071, ISSN: 0044-8249

Journal article

Bures Amat J, Blackmond DG, armstrong A, 2016, Explaining Anomalies in Enamine Catalysis: “Downstream Species” as a New Paradigm for Stereocontrol, Accounts of Chemical Research, ISSN: 1520-4898

Journal article

Bures Amat J, 2016, A Simple Graphical Method to Determine the Order in Catalyst, Angewandte Chemie - International Edition, ISSN: 1433-7851

A graphical analysis to elucidate the order in catalyst is presented. This analysis uses a normalized time scale, t [cat]Tn, to adjust entire reaction profiles constructed with concentration data. The method is fast and simple to perform because it directly uses the concentration data, therefore avoiding the data handling that is usually required to extract rates. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile.

Journal article

Bures J, Dingwall P, Armstrong A, Blackmond DGet al., 2014, Rationalization of an Unusual Solvent-Induced Inversion of Enantio-meric Excess in Organocatalytic Selenylation of Aldehydes, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 53, Pages: 8700-8704, ISSN: 1433-7851

Journal article

Isart C, Bures J, Vilarrasa J, 2014, Electrospray ionization mass spectra of the reactions of NaAuBr4 and related aurates with nucleophiles, JOURNAL OF MASS SPECTROMETRY, Vol: 49, Pages: 331-334, ISSN: 1076-5174

Journal article

Burés J, Armstrong A, Blackmond DG, 2013, The interplay of thermodynamics and kinetics in dictating organocatalytic reactivity and selectivity, Pure and Applied Chemistry, Pages: 1-1, ISSN: 0033-4545

Journal article

Bures J, Armstrong A, Blackmond DG, 2012, Curtin-Hammett Paradigm for Stereocontrol in Organocatalysis by Diarylprolinol Ether Catalysts, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: {6741-6750}-{6741-6750}, ISSN: 0002-7863

Detailed mechanistic study of two reactions catalyzed by diarylprolinol ether catalysts, the conjugate addition of aldehydes to nitro-olefins and the alpha-chlorination of aldehydes, leads to the proposal that the stereochemical outcome in these cases is not determined by the transition state of the step in which the stereogenic center is formed from enamine attack on the electrophile but instead is correlated with the relative stability and reactivity of diastereomeric intermediates downstream in the catalytic cycle. This combination of kinetic and thermodynamic factors illustrates a remarkable Curtin-Hammett scenario that can result in either an enhancement or an erosion of the selectivity that would be predicted by the transition state for enamine attack on the electrophile. Evidence is offered to suggest that this concept may represent a general phenomenon for pyrrolidine-based catalysts lacking an acidic directing proton. Implications for catalyst and reaction design are discussed.

Journal article

Sanchez D, Bastida D, Bures J, Isart C, Pineda O, Vilarrasa Jet al., 2012, Relative Tendency of Carbonyl Compounds To Form Enamines, ORGANIC LETTERS, Vol: 14, Pages: {536-539}-{536-539}, ISSN: 1523-7060

Equilibria between carbonyl compounds and their enamines (from O-TBDPS-derived prolinol) have been examined by NMR spectroscopy in DMSO-d(6). By comparing the exchange reactions between pairs (enamine A + carbonyl B -> carbonyl A + enamine B), a quite general scale of the tendency of carbonyl groups to form enamines has been established. Aldehydes quickly give enamines that are relatively more stable than those of ketones, but there are exceptions to this expected rule; for example, 1,3-dihydroxyacetone acetals or 3,5-dioxacyclohexanones (2-phenyl-1, 3-dioxan-5-one and 2,2-dimethy1-1,3-dioxan-5-one) show a greater tendency to afford enamines than many alpha-substituted aldehydes.

Journal article

Bures J, Armstrong A, Blackmond DG, 2012, Kinetic correlation between aldehyde/enamine stereoisomers in reactions between aldehydes with alpha-stereocenters and chiral pyrrolidine-based catalysts, CHEMICAL SCIENCE, Vol: 3, Pages: {1273-1277}-{1273-1277}, ISSN: 2041-6520

The formation of enamines between aldehydes with alpha-stereocenters and pyrrolidine-based catalysts that lack an acidic proton is examined by kinetic and spectroscopic studies. The reaction exhibits “kinetic stereospecificity” in that each enantiomer of the aldehyde initially reacts to form a specific enamine stereoisomer, prior to thermodynamic equilibration of the E and Z enamines. For the case of prolinate catalysts, each of the stereoisomeric enamines is correlated with a specific stereoisomeric oxazolidinone. The reactions of E and Z enamines with electrophiles such as DEAD lead to products of opposite stereochemistry. The product enantioselectivity observed depends on the extent to which the E and Z enamines are pre-equilibrated prior to reaction with the electrophile. General implications for selectivity in organocatalytic reactions are discussed.

Journal article

Hein JE, Bures J, Lam Y-H, Hughes M, Houk KN, Armstrong A, Blackmond DGet al., 2011, Enamine Carboxylates as Stereodetermining Intermediates in Prolinate Catalysis, ORGANIC LETTERS, Vol: 13, Pages: {5644-5647}-{5644-5647}, ISSN: 1523-7060

Experimental and computational studies probing the nature of Intermediates in the alpha-amination of aldehydes catalyzed by prolinate salts support an enamine carboxylate intermediate in the stereodetermining step.

Journal article

Bures J, Armstrong A, Blackmond DG, 2011, Mechanistic Rationalization of Organocatalyzed Conjugate Addition of Linear Aldehydes to Nitro-olefins, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 133, Pages: {8822-8825}-{8822-8825}, ISSN: 0002-7863

Kinetic studies of the conjugate addition of propanal to nitrostyrene catalyzed by diarylprolinol ethers reveal that formation of the product iminium species is rate-determining and is promoted by both the reaction product and acid additives. The beneficial role of a dominant cyclobutane intermediate in maintaining high stereoselectivity is highlighted. This mechanistic understanding led to the design of highly productive reaction protocols.

Journal article

Isart C, Bastida D, Bures J, Vilarrasa Jet al., 2011, Gold(III) Complexes Catalyze Deoximations/Transoximations at Neutral pH, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 50, Pages: 3275-3279, ISSN: 1433-7851

Journal article

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