AI Article Synopsis

  • The study used density functional theory to investigate how cycloadditions of tetrachloro-o-benzoquinone and 6,6-dimethylfulvene occur at the molecular level.
  • It identified that primary interactions help stabilize certain transition states, specifically in the endo reaction pathways.
  • The results showed that these transition states lead to various types of adducts that can transform into each other through specific shift reactions, and the effect of substituents on the selectivity of the reactions was also looked into.

Article Abstract

The reaction mechanism of cycloadditions of tetrachloro-o-benzoquinone with 6,6-dimethylfulvene were systematically investigated with density functional theory calculations. It was found that conditional primary interactions stabilize the ambimodal transition states in the endo pathways. Ambimodal transition states lead to [6 + 4]/[4 + 2] adducts or [4 + 2]/[2 + 4] adducts, which interconvert through 3,3-sigmatropic shift reactions. The substituent effects on periselectivity were also investigated.

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcc.27264DOI Listing

Publication Analysis

Top Keywords

ambimodal transition
12
transition states
12
cycloadditions tetrachloro-o-benzoquinone
8
tetrachloro-o-benzoquinone 66-dimethylfulvene
8
periselectivity ambimodal
4
states cycloadditions
4
66-dimethylfulvene reaction
4
reaction mechanism
4
mechanism cycloadditions
4
66-dimethylfulvene systematically
4

Similar Publications

Using the Theozyme Model to Study the Dynamical Mechanism of the Post-Transition State Bifurcation Reaction by NgnD Enzyme.

Molecules

November 2024

Henan-Macquarie University Joint Centre for Biomedical Innovation, Henan Key Laboratory of Brain Targeted Bio-Nanomedicine, School of Life Sciences, Henan University, Kaifeng 475004, China.

Post-transition state bifurcation (PTSB) is a fundamental process in which a single transition state leads to multiple products. This phenomenon is important in both biological and chemical contexts and offers valuable insights into reaction mechanisms and their applications. The theozyme model, which focuses on key residues within enzymes, offers a computationally efficient method for studying these processes while preserving the enzyme's catalytic properties.

View Article and Find Full Text PDF

Interplay between Energy and Entropy Mediates Ambimodal Selectivity of Cycloadditions.

J Chem Theory Comput

December 2024

Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.

One ambimodal transition state can lead to the formation of multiple products. However, it remains fundamentally unknown how the energy and entropy along the post-TS pathways mediate ambimodal selectivity. Here, we investigated the energy and entropy profiles along the post-TS pathways in four [4 + 2]/[6 + 4] cycloadditions.

View Article and Find Full Text PDF

Molecular Dynamics of the Davies Ambimodal C-H Functionalization/Cope Rearrangement Reaction.

J Org Chem

December 2024

Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.

The mechanism of the dirhodium-catalyzed combined C-H functionalization/Cope rearrangement (CH/Cope) reaction discovered by the Davies group has been investigated with density functional theory (DFT) calculations and quasi-classical molecular dynamics (MD) simulations. Computations from the Davies group previously showed that there is a post-transition state bifurcation leading to a direct CH reaction and also to the CH/Cope product. While this work was in preparation, the Tantillo group and the Ess group independently reported quantum mechanical and molecular dynamics studies on the dirhodium-tetracarboxylate-catalyzed diazoester CH/Cope and CH insertion reactions with 1,3-cyclohexadiene and 1,4-cyclohexadiene, respectively.

View Article and Find Full Text PDF

The latent singlet diradical character of the parent -quinonedimethide (-QDM), as revealed by valence bond calculations, is demonstrated experimentally by trapping with the kinetically stable free radical TEMPO at room temperature. In the absence of TEMPO, the main pathway for decomposition at ambient temperature is not (as previously proposed in the literature) a radical reaction but instead a concerted Diels-Alder dimerization, which through ωB97X-D/aug-cc-pVTZ/SMD//M06-2X-D3/6-31+G(d,p)/SMD calculations is shown to proceed through an ambimodal bispericyclic transition state. The predominantly non-radical reactivity of -QDM at room temperature differs from that of its isomeric -quinonedimethide (-QDM) congener, which self-reacts through radical pathways.

View Article and Find Full Text PDF

CH (tetradecapentaene) is a simple model system exhibiting post transition-state behavior, wherein both the (6 + 4) and (4 + 2) cycloaddition products are formed from one ambimocal transition state structure. We studied the bifurcation dynamics starting from the two ambimodal transition state structures, the chair-form and boat-form, using the quasi-classical trajectory, classical molecular dynamics, and ring-polymer molecular dynamics methods on the parameter-optimized semiempirical GFN2-xTB potential energy surface. It was found that the calculated branching fractions differ between the chair-form and boat-form due to the different nature in the IRC pathways.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!