G. Richard Stephenson | University of East Anglia (original) (raw)

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Papers by G. Richard Stephenson

Research paper thumbnail of Organometallic complexes as anion hosts

Research paper thumbnail of Transition Metal Organometallics for Organic Synthesis. VonF. J. McQuillin, D. G. Parker undG. R. Stephenson. Cambridge University Press, Cambridge, 1991. XII, 594 S., geb. 100.00 £ – ISBN 0-521-33353-9

Research paper thumbnail of CCDC 1479260: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1934883: Experimental Crystal Structure Determination

Research paper thumbnail of Spectroscopic, Structural and DFT Study of the Responses of Carbonylmetal Crown Ether Complexes to Alkali Metal Cations

European Journal of Inorganic Chemistry, 2011

Research paper thumbnail of Synthesis of Novel Stilbene–Coumarin Derivatives and Antifungal Screening of Monotes kerstingii-Specialized Metabolites Against Fusarium oxysporum

Antibiotics, 2020

Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural pr... more Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural productivity worldwide. Current chemical fungicides exhibit toxicity against non-target organisms, triggering negative environmental impact, and are a danger to consumers. In order to explore the chemical diversity of plants for potential antifungal applications, crude extract and fractions from Monotes kerstingii were screened for their activity against two multi-resistant Fusarium oxysporum strains: Fo32931 and Fo4287. Antifungal activity was evaluated by the determination of minimum inhibitory concentration (MIC) by broth dilution of fermentative yeasts using kinetic OD600 nm reading by a spectrophotometer. The n-butanol fraction showed the best activity against Fo4287. We screened eleven previously reported natural compounds isolated from different fractions, and a stilbene–coumarin 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-4,7-dimethoxy-3-methyl-2H-1-benzopyran-2-one (1) was the most active...

Research paper thumbnail of Front Cover: Induction of Planar Chirality Using Asymmetric Click Chemistry by a Novel Desymmetrisation of 1,3-Bisalkynyl Ferrocenes (Eur. J. Org. Chem. 43/2019)

European Journal of Organic Chemistry, 2019

Research paper thumbnail of Discovery of Small Molecule WWP2 Ubiquitin Ligase Inhibitors

Chemistry - A European Journal, 2018

Research paper thumbnail of Bioinspired, Base- and Metal-Free, Mild Decarboxylative Aldol Activation of Malonic Acid Half Thioesters Under Phase-Transfer Reaction Conditions

Advanced Synthesis & Catalysis, 2015

Utilizing ‘off the shelf’ commercially available, cheap, small synthetic molecules that mimic the... more Utilizing ‘off the shelf’ commercially available, cheap, small synthetic molecules that mimic the efficient mediation of important bioreactions utilized by Nature is not only highly sought after but also currently highly topical. This paper details our preliminary efforts at developing a unique base- and metal-free phase-transfer-mediated malonic acid thioester (MAHT) ‘activation protocol’ that efficiently generates (±)-β-thioesters. Our bioinspired aldol process is exceptionally mild, conducted under near neutral pH reaction conditions, does not require an inert, oxygen-free atmosphere or anhydrous reaction conditions and is highly atom-economic. Exemplifying the utility of our protocol, the synthesis of an array of structurally and functionally diverse (±)-β-hydroxy thioesters equipped with highly prized functionality, i.e., chlorine, bromine, fluorine, nitrile and nitro groups, is reported, as is the diastereoselective potential of this important reaction.

Research paper thumbnail of Malonic Acid Half Oxyesters and Thioesters: Solvent-Free Synthesis and DFT Analysis of Their Enols

Research paper thumbnail of Intramolecular Asymmetric Heck Reactions: Evidence for Dynamic Kinetic Resolution Effects

Research paper thumbnail of Electrophilic C 12 Building Blocks for Alkaloids:  Formal Total Synthesis of (±)-Maritidine

Research paper thumbnail of Chemical Characterisation of Disruptants of the Streptomyces coelicolor A3(2). ActVI Genes Involved in Actinorhodin Biosynthesis

The Journal of Antibiotics, 2000

Research paper thumbnail of Induction of Planar Chirality Using Asymmetric Click Chemistry by a Novel Desymmetrisation of 1,3-Bisalkynyl Ferrocenes‡

European Journal of Organic Chemistry, 2019

Research paper thumbnail of Unusual Nucleophilic Addition of Grignard Reagents in the Synthesis of 4-Amino-pyrimidines

Research paper thumbnail of Asymmetric Oxidation of Enol Derivatives to α-Alkoxy Carbonyls Using Iminium Salt Catalysts: A Synthetic and Computational Study

The Journal of Organic Chemistry

Research paper thumbnail of Transition-metal mediated asymmetric synthesis. Part 3. Preparation and stereospecific alkylation of unsymmetrically substituted tricarbonyl(cyclohexadienyl)iron(1+) salts: an organometallic approach to the synthesis of carvone, cryptomerion, and bilobanone

Journal of the Chemical Society, Perkin Transactions 1

Tricarbonyl(η5-3-methoxy-2-methylcyclohexa-2,4-dienyl)iron(1+)hexafluorophosphate(1–) has been pr... more Tricarbonyl(η5-3-methoxy-2-methylcyclohexa-2,4-dienyl)iron(1+)hexafluorophosphate(1–) has been prepared by a novel method based on thallium(III) oxidation. The opposite substitution pattern is obtained by hydride abstraction. Alkylation by bis(1-methylethenyl)cadmium, to introduce an olefinic side-chain, has been shown to be stereospecific for the α-face, and removal of the metal affords the expected enones. (±)-Carvone and -sylvecarvone have been prepared by this means. The results indicate the importance of regiocontrol of alkylation if chiral salts are to be employed in synthesis.

Research paper thumbnail of Optically active tricarbonyl(cyclohexadienyl)iron(1+) salts: Synthetic equivalents to spatially directed organic cations

Tetrahedron Letters

Optically active tricarbonyl (cyclohexdienyl)iron(1+) salts I, II and III are examples of olefin ... more Optically active tricarbonyl (cyclohexdienyl)iron(1+) salts I, II and III are examples of olefin complexes with moleoular asymmetry due to coordination uith a transition metal. Their reactions serve to direct the eventual specific formation of a new chiral centre of known absolute ...

Research paper thumbnail of ChemInform Abstract: Design of Asymmetric Synthesis

Research paper thumbnail of ChemInform Abstract: Ester Functionalized Alkene-Extended Cyclohexadienyliron Complexes

ChemInform

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Research paper thumbnail of Organometallic complexes as anion hosts

Research paper thumbnail of Transition Metal Organometallics for Organic Synthesis. VonF. J. McQuillin, D. G. Parker undG. R. Stephenson. Cambridge University Press, Cambridge, 1991. XII, 594 S., geb. 100.00 £ – ISBN 0-521-33353-9

Research paper thumbnail of CCDC 1479260: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Research paper thumbnail of CCDC 1934883: Experimental Crystal Structure Determination

Research paper thumbnail of Spectroscopic, Structural and DFT Study of the Responses of Carbonylmetal Crown Ether Complexes to Alkali Metal Cations

European Journal of Inorganic Chemistry, 2011

Research paper thumbnail of Synthesis of Novel Stilbene–Coumarin Derivatives and Antifungal Screening of Monotes kerstingii-Specialized Metabolites Against Fusarium oxysporum

Antibiotics, 2020

Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural pr... more Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural productivity worldwide. Current chemical fungicides exhibit toxicity against non-target organisms, triggering negative environmental impact, and are a danger to consumers. In order to explore the chemical diversity of plants for potential antifungal applications, crude extract and fractions from Monotes kerstingii were screened for their activity against two multi-resistant Fusarium oxysporum strains: Fo32931 and Fo4287. Antifungal activity was evaluated by the determination of minimum inhibitory concentration (MIC) by broth dilution of fermentative yeasts using kinetic OD600 nm reading by a spectrophotometer. The n-butanol fraction showed the best activity against Fo4287. We screened eleven previously reported natural compounds isolated from different fractions, and a stilbene–coumarin 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-4,7-dimethoxy-3-methyl-2H-1-benzopyran-2-one (1) was the most active...

Research paper thumbnail of Front Cover: Induction of Planar Chirality Using Asymmetric Click Chemistry by a Novel Desymmetrisation of 1,3-Bisalkynyl Ferrocenes (Eur. J. Org. Chem. 43/2019)

European Journal of Organic Chemistry, 2019

Research paper thumbnail of Discovery of Small Molecule WWP2 Ubiquitin Ligase Inhibitors

Chemistry - A European Journal, 2018

Research paper thumbnail of Bioinspired, Base- and Metal-Free, Mild Decarboxylative Aldol Activation of Malonic Acid Half Thioesters Under Phase-Transfer Reaction Conditions

Advanced Synthesis & Catalysis, 2015

Utilizing ‘off the shelf’ commercially available, cheap, small synthetic molecules that mimic the... more Utilizing ‘off the shelf’ commercially available, cheap, small synthetic molecules that mimic the efficient mediation of important bioreactions utilized by Nature is not only highly sought after but also currently highly topical. This paper details our preliminary efforts at developing a unique base- and metal-free phase-transfer-mediated malonic acid thioester (MAHT) ‘activation protocol’ that efficiently generates (±)-β-thioesters. Our bioinspired aldol process is exceptionally mild, conducted under near neutral pH reaction conditions, does not require an inert, oxygen-free atmosphere or anhydrous reaction conditions and is highly atom-economic. Exemplifying the utility of our protocol, the synthesis of an array of structurally and functionally diverse (±)-β-hydroxy thioesters equipped with highly prized functionality, i.e., chlorine, bromine, fluorine, nitrile and nitro groups, is reported, as is the diastereoselective potential of this important reaction.

Research paper thumbnail of Malonic Acid Half Oxyesters and Thioesters: Solvent-Free Synthesis and DFT Analysis of Their Enols

Research paper thumbnail of Intramolecular Asymmetric Heck Reactions: Evidence for Dynamic Kinetic Resolution Effects

Research paper thumbnail of Electrophilic C 12 Building Blocks for Alkaloids:  Formal Total Synthesis of (±)-Maritidine

Research paper thumbnail of Chemical Characterisation of Disruptants of the Streptomyces coelicolor A3(2). ActVI Genes Involved in Actinorhodin Biosynthesis

The Journal of Antibiotics, 2000

Research paper thumbnail of Induction of Planar Chirality Using Asymmetric Click Chemistry by a Novel Desymmetrisation of 1,3-Bisalkynyl Ferrocenes‡

European Journal of Organic Chemistry, 2019

Research paper thumbnail of Unusual Nucleophilic Addition of Grignard Reagents in the Synthesis of 4-Amino-pyrimidines

Research paper thumbnail of Asymmetric Oxidation of Enol Derivatives to α-Alkoxy Carbonyls Using Iminium Salt Catalysts: A Synthetic and Computational Study

The Journal of Organic Chemistry

Research paper thumbnail of Transition-metal mediated asymmetric synthesis. Part 3. Preparation and stereospecific alkylation of unsymmetrically substituted tricarbonyl(cyclohexadienyl)iron(1+) salts: an organometallic approach to the synthesis of carvone, cryptomerion, and bilobanone

Journal of the Chemical Society, Perkin Transactions 1

Tricarbonyl(η5-3-methoxy-2-methylcyclohexa-2,4-dienyl)iron(1+)hexafluorophosphate(1–) has been pr... more Tricarbonyl(η5-3-methoxy-2-methylcyclohexa-2,4-dienyl)iron(1+)hexafluorophosphate(1–) has been prepared by a novel method based on thallium(III) oxidation. The opposite substitution pattern is obtained by hydride abstraction. Alkylation by bis(1-methylethenyl)cadmium, to introduce an olefinic side-chain, has been shown to be stereospecific for the α-face, and removal of the metal affords the expected enones. (±)-Carvone and -sylvecarvone have been prepared by this means. The results indicate the importance of regiocontrol of alkylation if chiral salts are to be employed in synthesis.

Research paper thumbnail of Optically active tricarbonyl(cyclohexadienyl)iron(1+) salts: Synthetic equivalents to spatially directed organic cations

Tetrahedron Letters

Optically active tricarbonyl (cyclohexdienyl)iron(1+) salts I, II and III are examples of olefin ... more Optically active tricarbonyl (cyclohexdienyl)iron(1+) salts I, II and III are examples of olefin complexes with moleoular asymmetry due to coordination uith a transition metal. Their reactions serve to direct the eventual specific formation of a new chiral centre of known absolute ...

Research paper thumbnail of ChemInform Abstract: Design of Asymmetric Synthesis

Research paper thumbnail of ChemInform Abstract: Ester Functionalized Alkene-Extended Cyclohexadienyliron Complexes

ChemInform

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

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