Exploring a general mechanistic map on NHC-catalyzed activation/transformation reactions of saturated carboxylic anhydrides

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(11), P. 2670 - 2679

Published: Jan. 1, 2023

A general mechanistic map involving multiple intermediates and pathways has been proposed systematically studied for NHC-catalyzed transformation reactions of saturated carboxylic anhydrides.

Language: Английский

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Mechanism and Origin of Stereoselectivity for the NHC-Catalyzed Desymmetrization Reaction for the Synthesis of Axially Chiral Biaryl Aldehydes

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(5), P. 3133 - 3142

Published: Feb. 15, 2024

Organocatalytic desymmetrization reaction is a powerful tool for constructing axial chirality, but the theoretical study on origin of stereoselectivity still lags behind even now. In this work, N-heterocyclic carbene (NHC)-catalyzed biaryl frameworks synthesis axially chiral aldehydes has been selected and theoretically investigated by using density functional theory (DFT). The fundamental pathway involves several steps, i.e., desymmetrization, formation Breslow oxidation, esterification, NHC regeneration. processes have identified as stereoselectivity-determining rate-determining steps. Further weak interaction analyses proved that C–H···O hydrogen bond C–H···π interactions are responsible stability key stereoselective transition states. This research contributes to understanding nature NHC-catalyzed reactions compounds.

Language: Английский

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Elucidating the mechanism and origin of stereoselectivity in the activation/transformation of an acetic ester catalyzed by an N-heterocyclic carbene

Physical Chemistry Chemical Physics, Journal Year: 2024, Volume and Issue: 26(5), P. 4320 - 4328

Published: Jan. 1, 2024

The detailed mechanism, origin of stereoselectivity and substrate catalyst effects are extensively investigated using DFT methods.

Language: Английский

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DFT study on isothiourea-catalyzed C–C bond activation of cyclobutenone: the role of the catalyst and the origin of stereoselectivity

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(13), P. 2662 - 2669

Published: Jan. 1, 2024

The mechanism of organocatalytic C-C bond activation have been theoretically investigated.

Language: Английский

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Revealing the nature of covalently tethered distonic radical anions in the generation of heteroatom-centered radicals: evidence for the polarity-matching PCET pathway

Chemical Science, Journal Year: 2024, Volume and Issue: 15(31), P. 12398 - 12409

Published: Jan. 1, 2024

The philicity-regulation and PCET mechanism of tether-tunable distonic radical anion-mediated generation heteroatom-centered radicals has been explored via experimental theoretical investigations.

Language: Английский

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N-Heterocyclic Carbene/Brønsted Acid Cooperatively Catalyzed Conversions of α, β-Unsaturated Carbonyls: Hydrogen Bond Donor/Acceptor-Electrophile/Nucleophile Combination Models

ACS Catalysis, Journal Year: 2022, Volume and Issue: 13(1), P. 612 - 623

Published: Dec. 22, 2022

Great success has been achieved in precisely constructing C–C bonds under N-heterocyclic carbene (NHC)/Brønsted acid (BA) cooperative catalysis. However, how NHC and BA co-catalyst accelerate conversions of α,β-unsaturated carbonyls remains unclear. Herein, we have systematically studied several representative NHC/BA catalysis models to help chemists better understand the nature these reactions. The favorable cooperatively catalyzed reactions were identified confirmed by proposed hydrogen bond donor/acceptor-electrophile/nucleophile combination rules reactivity index (denoted as Rk). This work should be important for understanding catalytic mechanism also provides valuable insights designing an efficient reaction with special selectivity.

Language: Английский

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Mechanism of a cobalt-catalyzed hydroarylation reaction and origin of stereoselectivity

Catalysis Science & Technology, Journal Year: 2022, Volume and Issue: 12(13), P. 4380 - 4387

Published: Jan. 1, 2022

In the present study, mechanism of a cobalt-catalyzed hydroarylation reaction between N -pyridylindole and 1,6-enynes origin its stereoselectivity have been systematically investigated using DFT calculation method.

Language: Английский

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Theoretical investigation on cobalt-catalyzed hydroacylation reaction: Mechanism and origin of stereoselectivity

Molecular Catalysis, Journal Year: 2022, Volume and Issue: 527, P. 112410 - 112410

Published: June 7, 2022

Language: Английский

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Computational and Experimental Confirmation of the Diradical Character of para-Quinonedimethide

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(29), P. 16037 - 16044

Published: July 18, 2023

The ground-state structure of the parent para-quinonedimethide (p-QDM) molecule is generally represented in its closed shell form, i.e., as a cyclic, nonaromatic, through-conjugated/cross-conjugated hybrid comprising four C═C bonds. Nonetheless, p-QDM has been theorized to contain contribution from open-shell aromatic singlet diradical form. VBSCF calculations identify an 29% structure, while CASPT2(16,16)/def2-TZVP and ωB97XD/aug-cc-pVTZ predict that dimerization proceeds along pathway with low (77 kJ/mol) barrier toward dimerization, which occurs by way C-C bond formation between exocyclic methylene carbons. A similar (98 exists reaction radical trap TEMPO. These predictions are verified experimentally through isolation bis-TEMPO-trapped p-QDM, coupled dimer, demonstrating mixture TEMPO can initiate polymerization n-butyl acrylate at ambient temperature. In contrast tetracyanoquinone (TCNQ) neither dimerizes nor reacts TEMPO, despite having character p-QDM. This lack reactivity consistent both higher kinetic thermodynamically unfavorable process, ascribed destabilizing steric clashes polar effects.

Language: Английский

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Deaminative radical reactions via relayed proton-coupled electron transfer

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 10(9), P. 2155 - 2164

Published: Jan. 1, 2023

The detailed mechanism of these kinds N-heterocyclic carbene-catalyzed deaminative radical reactions has been explored in theory for the first time.

Language: Английский

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