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

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

Uncovering a general oxidation model of nitrogen-containing oxidant in N-heterocyclic carbene (NHC) catalyzed oxidative reactions of aldehydes

Molecular Catalysis, Journal Year: 2024, Volume and Issue: 569, P. 114538 - 114538

Published: Sept. 13, 2024

Language: Английский