- Catalytic performance and mechanism of Cu(II)-hydrazone complexes as models of galactose oxidase
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As simulants of galactose oxidase (GO), three mononuclear Cu(II) complexes with 1-((3-t-Bu,5-R1)-salicylidenehydrazono),2-((3-t-Bu,5-R2)- salicylidenehydrazono)-1,2-diphenylethane (H2LBu,Bu: R1 = R2 = t-butyl; H2LMeO,
- Shi, Huatian,Yin, Yegao
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- Salen/salan metallic complexes as redox labels for electrochemical aptasensors
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This work presents the synthesis and characterization of salen/salan metal complexes for their future application as electrochemical labels in affinity sensors. Due to its stability and electrochemical properties, an oxovanadium salan complex was selected
- Ben Jrad, Amani,Kanso, Hussein,Raviglione, Delphine,Noguer, Thierry,Inguimbert, Nicolas,Calas-Blanchard, Carole
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- Stereoselective protonation of 2-methyl-1-tetralone lithium enolate catalyzed by salan-type diamines
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Asymmetric protonation of ketone enolates is a convenient alternative to asymmetric alkylation of enolates that allows to convert racemic ketones into their optically active form. Here, we have reported an efficient enantioselective protonation of 2-methyl-1-tetralone lithium enolate catalyzed by salan-type diamines. A broad series of salan-type catalysts were synthesized, including several previously unknown, and subsequently tested in the title reaction. For the first time, a chiral amine used as organocatalyst has shown better results than as stoichiometric protonating agent. Application of only 10 mol% of salan allows to obtain the title ketone with high yield and enantiomeric excess up to 75%. The DFT calculations of the structure of the catalyst and its complex with lithium enolate were conducted, which makes it possible to propose a likely reaction mechanism.
- ?owicki, Daniel,Watral, Justyna,Jelecki, Maciej,Bohusz, Wiktor,Kwit, Marcin
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supporting information
(2021/04/02)
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- Elaboration on the Electronics of Salen Manganese Nitrides: Investigations into Alkoxy-Substituted Ligand Scaffolds
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The ligand electronics of salen manganese nitride complexes directly influence the locus of oxidation and, thus, the reactivity of the resulting oxidized species. This work investigates the influence of tert-butoxy, isopropoxy, and methoxy substituents on
- Hein, Nicholas M.,Macneil, Gregory A.,Storr, Tim
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p. 16895 - 16905
(2021/11/18)
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- Carbonylative, Catalytic Deoxygenation of 2,3-Disubstituted Epoxides with Inversion of Stereochemistry: An Alternative Alkene Isomerization Method
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Reactions facilitating inversion of alkene stereochemistry are rare, sought-after transformations in the field of modern organic synthesis. Although a number of isomerization reactions exist, most methods require specific, highly activated substrates to achieve appreciable conversion without side product formation. Motivated by stereoinvertive epoxide carbonylation reactions, we developed a two-step epoxidation/deoxygenation process that results in overall inversion of alkene stereochemistry. Unlike most deoxygenation systems, carbon monoxide was used as the terminal reductant, preventing difficult postreaction separations, given the gaseous nature of the resulting carbon dioxide byproduct. Various alkyl-substituted cis- A nd trans-epoxides can be reduced to trans- A nd cis-alkenes, respectively, in >99:1 stereospecificity and up to 95% yield, providing an alternative to traditional, direct isomerization approaches.
- Lamb, Jessica R.,Hubbell, Aran K.,MacMillan, Samantha N.,Coates, Geoffrey W.
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supporting information
p. 8029 - 8035
(2020/05/01)
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- Unprecedented reductive cyclisation of salophen ligands to tetrahydroquinoxalines during metal complex formation
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The synthesis of novel tetrahydroquinoxalines by a metal induced one-electron reductive cyclisation of salophen ligands was found to occur when a salophen ligand was treated with chromium(ii) chloride or decamethylcobaltocene.
- Dowsett, Mark R.,Lamb, Katie J.,North, Michael,Parker, Rachel R.,Whitwood, Adrian C.
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supporting information
p. 4844 - 4847
(2020/05/13)
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- Mechanism-Inspired Design of Bifunctional Catalysts for the Alternating Ring-Opening Copolymerization of Epoxides and Cyclic Anhydrides
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Advances in catalysis have enabled the ring-opening copolymerization of epoxides and cyclic anhydrides to afford structurally and functionally diverse polyesters with controlled molecular weights and dispersities. However, the most common systems employ b
- Abel, Brooks A.,Lidston, Claire A. L.,Coates, Geoffrey W.
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supporting information
p. 12760 - 12769
(2019/08/26)
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- Development of Highly Active and Regioselective Catalysts for the Copolymerization of Epoxides with Cyclic Anhydrides: An Unanticipated Effect of Electronic Variation
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Recent developments in polyester synthesis have established several systems based on zinc, chromium, cobalt, and aluminum catalysts for the ring-opening alternating copolymerization of epoxides with cyclic anhydrides. However, to date, regioselective proc
- Diciccio, Angela M.,Longo, Julie M.,Rodríguez-Calero, Gabriel G.,Coates, Geoffrey W.
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supporting information
p. 7107 - 7113
(2016/07/06)
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- A new cobalt-salen catalyst for asymmetric cyclopropanation. Synthesis of the serotonin-norepinephrine repuptake inhibitor (+)-synosutine
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A new C2 symmetric cobalt(II)-salen catalyst based on cis-2,5-diaminobicyclo[2.2.2]octane as the chiral scaffold was prepared which, in the presence of potassium thioacetate as the promoter, catalyzed the formation of cyclopropanes from 1,1-dis
- White, James D.,Shaw, Subrata
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supporting information
p. 3880 - 3883
(2014/08/18)
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- One-electron oxidation of electronically diverse manganese(III) and nickel(II) salen complexes: Transition from localized to delocalized mixed-valence ligand radicals
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Ligand radicals from salen complexes are unique mixed-valence compounds in which a phenoxyl radical is electronically linked to a remote phenolate via a neighboring redox-active metal ion, providing an opportunity to study electron transfer from a phenola
- Kurahashi, Takuya,Fujii, Hiroshi
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supporting information; experimental part
p. 8307 - 8316
(2011/07/08)
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- Awakening a dormant catalyst: Salicylaldimine systems for ethene/tert-butylstyrene copolymerization
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A group of readily available zirconium catalysts incapable of ethene-co-styrene polymerization are remarkably active and selective for the production of the new polymer ethene-co-tert-butylstyrene via a single site mechanism.
- Theaker, Giles W.,Morton, Colin,Scott, Peter
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supporting information; experimental part
p. 6883 - 6885
(2009/04/13)
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- A Class of Ligands Designed as Model for Apogalactose Oxidase
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Seven tripodal tetradentate ligands bearing one pyridine and two diversely substituted phenolic arms, designed as models for apogalactose oxidase, have been synthesized.Electrochemical one-electron oxidation of acetonitrile solutions of the ligands led to
- Menage, Stepane,Gellon, Gisele,Pierre, Jean-Louis,Zurita, Dacil,Saint-Aman, Eric
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p. 785 - 792
(2007/10/03)
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