Theoretical Insights into Rare-Earth-Catalyst-Controlled Diastereo- and Enantioselective [3 + 2] Annulation of Aromatic Aldimines with Styrenes

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 5, 2025

Rare-earth-catalyzed annulation reactions using alkenes via C–H activation offer an atom-efficient approach to constructing cyclic compounds. However, the mechanisms underlying these remain poorly understood, limiting rational design of related catalytic systems. Recently, Hou and Cong reported unprecedented example rare-earth-catalyst-controlled diastereodivergent asymmetric [3 + 2] aromatic aldimines with alkenes. To elucidate origins diastereo- enantioselectivity, density functional theory calculations were performed. The results revealed that styrene insertion step determines stereoselectivity. Styrene follows a similar metal–styrene interaction pattern across different catalysts. Specifically, during cis-insertion, interacts strongly metal center, exhibiting significant Sc···Ph interactions, whereas such interactions are absent trans-insertion. Thus, when catalyst is employed small ligand, stereoselectivity primarily governed by electronic factors, favoring cis-insertion mode. In contrast, for more sterically hindered catalyst, in insufficient overcome steric effects, leading preference trans-insertion mode, which minimizes hindrance. These findings deeper insights into catalyst-controlled enantioselectivity will also contribute stereospecific rare-earth catalysis.

Language: Английский

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Theoretical investigation on the reaction mechanism and origin of stereoselectivity of a three-component coupling reaction under organocatalysis

Molecular Catalysis, Journal Year: 2025, Volume and Issue: 573, P. 114819 - 114819

Published: Jan. 6, 2025

Language: Английский

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Theoretical Studies on the Competing Mechanism and Origin of Diastereoselectivity of NHC-Catalyzed Intramolecular [3 + 2] Annulations of Ynals

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: March 5, 2025

Chiral tricyclic 6,5,5-fused rings exhibit structural diversity and possess important biological activities in the synthesis of natural products. However, predicting possible mechanism origin stereoselectivity these reactions remains a challenge. In this article, we conducted theoretical investigation into NHC-catalyzed intramolecular [3 + 2] annulations ynals to generate rings. Our calculations revealed that NHC could nucleophilically attack carbonyl group ynal reactant, leading formation Breslow intermediate via 1,2-proton transfer. Subsequently, an Michael addition takes place, resulting 6-5 bicyclic intermediate. We then compared competitive processes involving proton transfer Mannich reaction. The more energetically favorable process involves HOAc-assisted process, followed by To ascertain diastereoselectivity, performed noncovalent interaction (NCI) atom-in-molecule (AIM) analyses. This work is useful for understanding general principles detailed mechanisms chiral scaffolds with unique diastereoselectivity.

Language: Английский

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Overlooked Ligand Role of Pyridine Substrate in Site Selectivity of Rare-Earth-Catalyzed C–H Alkylation with Alkenes

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 11, 2025

The rare-earth-catalyzed C-H alkylation of heteroatom-containing substrates with alkenes has been extensively studied over the past decade. Traditionally, those have regarded primarily as reactants in these reactions. In this study, mechanism 2-ethylpyridine styrene was investigated by DFT calculations, revealing often-overlooked ligand effect pyridine substrates. Our findings demonstrate that substrates, acting ligands, play a pivotal role modulating site selectivity during activation. These results enhance our understanding rare-earth catalysis and provide valuable insights into its versatile reactivity, offering novel perspective on dual roles (both reactant ligand) which are widely used functionalization

Language: Английский

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Mechanistic studies on phosphine-catalyzed [4 + 3] annulation of β′-acetoxy allenoate with 1C,3N-dinucleophile

Computational and Theoretical Chemistry, Journal Year: 2024, Volume and Issue: 1241, P. 114924 - 114924

Published: Oct. 19, 2024

Language: Английский

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DFT Study on the Mechanism of Phosphine-Catalyzed Ring-Opening Reaction of Cyclopropyl Ketone

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

In the present study, mechanism, origin of chemoselectivity, and substituent effects phosphine-catalyzed ring-opening reaction cyclopropyl ketone have been investigated using DFT method. Multiple pathways, including formation hydrofluorenone, Cloke-Wilson product, cyclopenta-fused were studied compared. The computational results show that pathway for hydrofluorenone is most favorable one, which involves four processes: nucleophilic substitution to open three-membered ring, an intramolecular Michael addition enolate intermediate, [1,5]-proton transfer give ylide, Wittig deliver final product. For disclosing structural analysis local reactivity index performed. Moreover, also considered QTAIM analysis. current study would provide useful insights understanding chemoselective reactions.

Language: Английский

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DFT Study in An Asymmetric Organocatalytic Homologation: Mechanism, Origin of Stereoselectivity

Asian Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 24, 2024

Abstract In the present study, mechanism, origin of stereoselectivity, and role catalyst organocatalytic homologation reaction between phenyl boronate trifluoromethyl diazomethane have been theoretically investigated using density functional theory (DFT) method. Based on calculations, in situ generated ethanol plays significant triggering reaction. Moreover, [1,2]‐boron migration process is stereoselectivity‐determining step, with S ‐configured isomer being predominantly. addition, NCI analysis performed to disclose stereoselectivity.

Language: Английский

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Elucidating the Mechanism and Selectivities of Cobalt‐Catalyzed Transformation of O‐Acyl Oxime

Applied Organometallic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 19, 2024

ABSTRACT In this work, the mechanistic investigation on cobalt‐catalyzed CH functionalization of O ‐acyl oxime and verification origin selectivities are employed using density functional theory (DFT) method. Based calculations, most energetically favorable pathway contains four steps: coordination Co(III) species to oxime, para ‐selective activation give a five‐membered cobaltacycle, [2,1]‐alkyne insertion, redox‐cyclization final product regenerate species. IRC calculations clearly indicate that process occurs in concerted but highly asynchronous manner. The structural analysis reveals ‐CH preferentially mainly due less steric hindrance. FMO energetic span model used disclose regioselectivity chemoselectivity, respectively.

Language: Английский

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