Chalcogen Bonding Catalysis: Tellurium, the Last Frontier?

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(69)

Published: Sept. 25, 2023

Chalcogen bonding (ChB) is the non-covalent interaction occurring between chalcogen atoms as Lewis acid sites and or groups of able to behave bases through their lone pair π electrons. Analogously its sister halogen bonding, high directionality this was implemented for precise structural organizations in solid state solution. Regarding catalysis, ChB now accepted a new mode activation demonstrated by increased number examples last five years. In family catalysts, those based on tellurium rapidly appeared overcome lighter sulfur selenium counterparts. review, we highlight properties tellurium-based derivatives solution summarize start-of-the-art applications catalysis.

Language: Английский

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Chalcogen- and Halogen-Bond-Donating Cyanoborohydrides Provide Imine Hydrogenation

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(5), P. 2916 - 2925

Published: Feb. 19, 2024

Sulfonium, selenonium, telluronium, and iodonium cyanoborohydrides have been synthesized, isolated, fully characterized by various methods, including single-crystal X-ray diffraction (XRD) analysis. The quantum theory of atoms in molecules' analysis based on the XRD data indicated that hydride···σ-hole short contacts observed crystal structures each compound a purely noncovalent nature. telluronium provide significantly higher rate model reaction imine hydrogenation compared with sodium tetrabutylammonium cyanoborohydrides. Based NMR high-resolution electrospray ionization mass spectrometry indicating progress is accompanied cation reduction, mechanism involving intermediate formation elusive onium hydrides has proposed as an alternative to conventional electrophilic activation moiety its ligation cation's σ-hole.

Language: Английский

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Enantioselective Synthesis of Tetra‐substituted 3‐Hydroxyphthalide Esters by Isothiourea‐Catalysed Acylative Dynamic Kinetic Resolution

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(37)

Published: May 7, 2024

Abstract A general and highly enantioselective method for the preparation of tetra‐substituted 3‐hydroxyphthalide esters via isothiourea‐catalysed acylative dynamic kinetic resolution (DKR) is reported. Using (2 S ,3 R )‐HyperBTM (5 mol %) as catalyst, scope limitations this methodology have been extensively probed, with high enantioselectivity good to excellent yields observed (>40 examples, up 99 %, : 1 er). Substitution aromatic core within skeleton, well aliphatic substitution at C(3), readily tolerated. diverse range anhydrides, including those from bioactive pharmaceutically relevant acids, can also be used. The in DKR process has probed computationally, a key substrate heteroatom donor O⋅⋅⋅acyl‐isothiouronium interaction identified through DFT analysis necessary enantiodiscrimination.

Language: Английский

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Influence of Coordination to Silver(I) Centers on the Activity of Heterocyclic Iodonium Salts Serving as Halogen‐Bond‐Donating Catalysts

ChemPlusChem, Journal Year: 2023, Volume and Issue: 88(10)

Published: Sept. 7, 2023

Kinetic data based on 1 H NMR monitoring and computational studies indicate that in solution, pyrazole-containing iodonium triflates silver(I) triflate bind to each other, such an interplay results the decrease of total catalytic activity mixture these Lewis acids compared separate catalysis Schiff condensation, imine-isocyanide coupling, or nucleophilic attack a triple carbon-carbon bond. Moreover, kinetic cooperation with prevention decomposition salts during reaction progress. XRD study confirms coordinates center via pyrazole N atom produce rare example pentacoordinated trigonal bipyramidal dinuclear complex featuring cationic ligands.

Language: Английский

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Cooperative Covalent–Noncovalent Organocatalysis of the Knoevenagel Condensation Based on an Amine and Iodonium Salt Mixture

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(12)

Published: Feb. 21, 2024

Abstract The experimentally obtained kinetic data has indicated the existence of a synergetic cocatalytic effect provided by an iodonium salt in base‐catalyzed Knoevenagel condensation. diphenyliodonium triflate serving as halogen bond‐donating Lewis acid provides higher than zinc(II) or triflic serving, respectively, metal cation‐based and Brønsted acid. Such remains same for broad scope carbonyl compounds covering aldehydes featuring electron‐withdrawing electron‐donating substituents, well ketone involved reaction.

Language: Английский

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Iodonium and Telluronium Triflates Serving as Noncovalent Organocatalysts Provide Catalytic Effect in the Schiff Condensation Due to Different Reasons

ChemCatChem, Journal Year: 2024, Volume and Issue: unknown

Published: June 15, 2024

Abstract Sulfonium, selenonium, telluronium triflates, as well chloronium, bromonium, and iodonium triflates have been examined in the model Schiff condensation chalcogen‐ halogen bond donating organocatalysts, respectively. The kinetic data indicated that catalytic effect of salt is provided via decrease enthalpy activation reaction, whereas – unexpectedly caused by value entropy activation. In addition, it was experimentally shown activity sulfonium selenonium salts significantly lower than chloronium bromonium salts, but latter pair species less stable under reaction conditions former pair.

Language: Английский

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Halonium and Chalconium Salt-Catalyzed Schiff Condensation: Kinetics and DFT Insights into Organocatalyst Activity Parameters

Organic & Biomolecular Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Chalconium and halonium salts catalyze Schiff condensation. Kinetic data DFT calculations show that the catalytic activity correlates with maximum electrostatic potential on σ-holes, whereas other factors are less significant.

Language: Английский

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Isothiourea‐Catalysed Acylative Dynamic Kinetic Resolution of Tetra‐substituted Morpholinone and Benzoxazinone Lactols

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(37)

Published: May 7, 2024

The development of methods to allow the selective acylative dynamic kinetic resolution (DKR) tetra-substituted lactols is a recognised synthetic challenge. In this manuscript, highly enantioselective isothiourea-catalysed DKR morpholinone and benzoxazinone-derived reported. scope limitations methodology have been developed, with high enantioselectivity good excellent yields (up 89 %, 99 : 1 er) observed across broad range substrate derivatives incorporating substitution at N(4) C(2), di- spirocyclic C(5) C(6), as well benzannulation (>35 examples in total). process amenable scale-up on g laboratory scale. factors leading selectivity probed through computation, an N-C=O⋅⋅⋅isothiouronium interaction identified key producing ester products enantioenriched form.

Language: Английский

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Organic Chemistry in Russian Universities. Achievements of Recent Years

Russian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 60(8), P. 1361 - 1584

Published: Aug. 1, 2024

Language: Английский

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Unexpected Inhibition of the Knoevenagel Condensation in Methanol by Iodonium Salt Served as Electrophilic Activator

Journal of Physical Organic Chemistry, Journal Year: 2025, Volume and Issue: 38(3)

Published: Feb. 14, 2025

ABSTRACT Halogen bond donors are recognized as electrophilic catalysts in reactions involving carbonyl compounds. This study describes an unexpected inhibition of the Knoevenagel condensation by catalyst. To elucidate intricacies mechanism, overall reaction order and rate constants were determined using 1 H NMR spectroscopy, further experiments with different nucleophiles conducted. The findings revealed that primary is attributed to a substantial acceleration side aldehyde methanolysis, which hinders formation final alkene product.

Language: Английский

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