Imperial College London

ProfessorAlanArmstrong

Faculty of Natural SciencesDepartment of Chemistry

Professor of Organic Synthesis
 
 
 
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Contact

 

+44 (0)20 7594 5876a.armstrong

 
 
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Location

 

501EMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Publication Type
Year
to

142 results found

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

Armstrong A, Emmerson DPG, Milner HJ, Sheppard RJet al., 2014, [2,3]-Sigmatropic Rearrangement of Allylic Selenimides: Strategy for the Synthesis of Peptides, Peptidomimetics, and <i>N</i>-Aryl Vinyl Glycines, JOURNAL OF ORGANIC CHEMISTRY, Vol: 79, Pages: 3895-3907, ISSN: 0022-3263

Journal article

Armstrong A, Pullin RDC, Jenner CR, Foo K, White AJP, Scutt JNet al., 2014, Tertiary amine-promoted enone aziridination: investigations into factors influencing enantioselective induction, TETRAHEDRON-ASYMMETRY, Vol: 25, Pages: 74-86, ISSN: 0957-4166

Journal article

Armstrong A, Boto RA, Dingwall P, Contreras-Garcia J, Harvey MJ, Mason NJ, Rzepa HSet al., 2014, The Houk-List transition states for organocatalytic mechanisms revisited, CHEMICAL SCIENCE, Vol: 5, Pages: 2057-2071, ISSN: 2041-6520

Journal article

Armstrong A, Braddock DC, Jones AX, Clark Set al., 2013, Catalytic asymmetric bromolactonization reactions using (DHQD)<sub>2</sub>PHAL-benzoic acid combinations, TETRAHEDRON LETTERS, Vol: 54, Pages: 7004-7008, ISSN: 0040-4039

Journal article

Struebing H, Ganase Z, Karamertzanis PG, Siougkrou E, Haycock P, Piccione PM, Armstrong A, Galindo A, Adjiman CSet al., 2013, Computer-aided molecular design of solvents for accelerated reaction kinetics, NATURE CHEMISTRY, Vol: 5, Pages: 952-957, ISSN: 1755-4330

Journal article

Collins JC, Armstrong A, Chapman KL, Cordingley HC, Jaxa-Chamiec AA, Judd KE, Mann DJ, Scott KA, Tralau-Stewart CJ, Low CMRet al., 2013, Prospective use of molecular field points in ligand-based virtual screening: efficient identification of new reversible Cdc25 inhibitors, MEDCHEMCOMM, Vol: 4, Pages: 1148-1155, ISSN: 2040-2503

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

Milner HJ, Armstrong A, 2013, Oxides and Epoxides, COMPREHENSIVE ENANTIOSELECTIVE ORGANOCATALYSIS: CATALYSTS, REACTIONS, AND APPLICATIONS, VOLS 1-3, Editors: Dalko, Publisher: BLACKWELL SCIENCE PUBL, Pages: 523-545, ISBN: 978-3-527-33236-6

Book chapter

Nonoo RH, Armstrong A, Mann DJ, 2012, Kinetic Template-Guided Tethering of Fragments, CHEMMEDCHEM, Vol: 7, Pages: 2082-2086, ISSN: 1860-7179

Journal article

Armstrong A, Ferguson A, 2012, Synthesis and ring openings of cinnamate-derived N-unfunctionalised aziridines, BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY, Vol: 8, Pages: 1747-1752, ISSN: 1860-5397

Journal article

Bures J, Armstrong A, Blackmond DG, 2012, Correction to Curtin-Hammett Paradigm for Stereocontrol in Organocatalysis by Diarylprolinol Ether Catalysts (vol 134, pg 6741, 2012), JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: {14264}-{14264}, ISSN: 0002-7863

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

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

Armstrong A, Deacon N, Donald C, 2011, Enantioselective Synthesis of α-Aminophosphonates via Organocatalytic Sulfenylation and [2,3]-Sigmatropic Sulfimide Rearrangement, SYNLETT, Pages: 2347-2350, ISSN: 0936-5214

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

Hein JE, Armstrong A, Blackmond DG, 2011, Kinetic profiling of prolinate-catalyzed α-amination of aldehydes., Org Lett, Vol: 13, Pages: 4300-4303

Deconvolution of the role of off-cycle species from the desired catalytic cycle leads to an optimized protocol for the prolinate-catalyzed amination of aldehydes. The scope of complex reaction networks will be greatly broadened by understanding ancillary rate processes that influence the productive catalytic pathway.

Journal article

Hein JE, Armstrong A, Blackmond DG, 2011, Kinetic Profiling of Prolinate-Catalyzed α-Amination of Aldehydes, ORGANIC LETTERS, Vol: 13, Pages: 4300-4303, ISSN: 1523-7060

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

Armstrong A, Emmerson DPG, 2011, Enantioselective Synthesis of α-Alkyl, α-Vinyl Amino Acids via [2,3]-Sigmatropic Rearrangement of Selenimides, ORGANIC LETTERS, Vol: 13, Pages: 1040-1043, ISSN: 1523-7060

Journal article

Struebing H, Ganase Z, Karamertzanis PG, Armstrong A, Galindo A, Adjiman CSet al., 2011, Solvent design for optimal kinetics: From quantum mechanical predictions to experimental validation, Pages: 39-40

Conference paper

Armstrong A, Bettati M, White AJP, 2010, Catalytic enantioselective alkene epoxidation using novel spirocyclic <i>N</i>-carbethoxy-azabicyclo[3.2.1]octanones, TETRAHEDRON, Vol: 66, Pages: 6309-6320, ISSN: 0040-4020

Journal article

Blackmond DG, Moran A, Hughes M, Armstrong Aet al., 2010, Unusual Reversal of Enantioselectivity in the Proline-Mediated α-Amination of Aldehydes Induced by Tertiary Amine Additives, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 132, Pages: 7598-+, ISSN: 0002-7863

Journal article

Armstrong A, Pullin RDC, Jenner CR, Scutt JNet al., 2010, Amine-Promoted Synthesis of Vinyl Aziridines, JOURNAL OF ORGANIC CHEMISTRY, Vol: 75, Pages: 3499-3502, ISSN: 0022-3263

Journal article

Armstrong A, Collins JC, 2010, Direct Azole Amination: C-H Functionalization as a New Approach to Biologically Important Heterocycles, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 49, Pages: 2282-2285, ISSN: 1433-7851

Journal article

Valera FE, Quaranta M, Moran A, Blacker J, Armstrong A, Cabral JT, Blackmond DGet al., 2010, The Flow's the Thing ... Or Is It? Assessing the Merits of Homogeneous Reactions in Flask and Flow, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 49, Pages: 2478-2485, ISSN: 1433-7851

Journal article

Zotova N, Moran A, Armstrong A, Blackmond DGet al., 2009, A Coherent Mechanistic Rationale for Additive Effects and Autoinductive Behaviour in Proline-Mediated Reactions, ADVANCED SYNTHESIS & CATALYSIS, Vol: 351, Pages: 2765-2769, ISSN: 1615-4150

Journal article

Armstrong A, Bhonoah Y, White AJP, 2009, Constrained β-Proline Analogues in Organocatalytic Aldol Reactions: The Influence of Acid Geometry, JOURNAL OF ORGANIC CHEMISTRY, Vol: 74, Pages: 5041-5048, ISSN: 0022-3263

Journal article

Zotova N, Broadbelt LJ, Armstrong A, Blackmond DGet al., 2009, Kinetic and mechanistic studies of proline-mediated direct intermolecular aldol reactions, BIOORGANIC & MEDICINAL CHEMISTRY LETTERS, Vol: 19, Pages: 3934-3937, ISSN: 0960-894X

Journal article

Armstrong A, Pyrkotis C, 2009, Synthetic studies on amphidinolides C and F: synthesis of the C18-C29 segment of amphidinolide F, TETRAHEDRON LETTERS, Vol: 50, Pages: 3325-3328, ISSN: 0040-4039

Journal article

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