scholarly journals Metal Bound or Free Ylides as Reaction Intermediates in Metal-Catalyzed [2,3]-Sigmatropic Rearrangements? It Depends

ACS Catalysis ◽  
2021 ◽  
pp. 829-839
Author(s):  
Croix J. Laconsay ◽  
Dean J. Tantillo
Keyword(s):  
Reaction Intermediates ◽  
Sigmatropic Rearrangements ◽  
Metal Catalyzed

scholarly journals Metal-Bound or Free Ylides as Reaction Intermediates in Metal-Catalyzed [2,3]-Sigmatropic Rearrangements? It Depends.

2020 ◽  
Author(s):  
Croix Laconsay ◽  
Dean Tantillo
Keyword(s):  
Density Functional Theory ◽  
Case Studies ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Metal Catalyst ◽  
Reaction Intermediates ◽  
Functional Theory ◽  
Sigmatropic Rearrangements ◽  
Metal Catalyzed

<p>Density functional theory calculations were applied to study four previously published metal-catalyzed [2,3]-rearrangements from onium ylide intermediates, in pursuit of generalizations about when, during these types of reactions, catalysts dissociate. Our results corroborate past studies where free ylide mechanisms were proposed to be operative. Calculations on case studies predict that the origin of metal-catalyst ‘falling off’ (dissociation) can be attributed primarily to the steric bulkiness of functional groups adjacent to the carbene carbon. </p>

scholarly journals Metal-Bound or Free Ylides as Reaction Intermediates in Metal-Catalyzed [2,3]-Sigmatropic Rearrangements? It Depends.

2020 ◽  
Author(s):  
Croix Laconsay ◽  
Dean Tantillo
Keyword(s):  
Density Functional Theory ◽  
Case Studies ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Metal Catalyst ◽  
Reaction Intermediates ◽  
Functional Theory ◽  
Sigmatropic Rearrangements ◽  
Metal Catalyzed

<p>Density functional theory calculations were applied to study four previously published metal-catalyzed [2,3]-rearrangements from onium ylide intermediates, in pursuit of generalizations about when, during these types of reactions, catalysts dissociate. Our results corroborate past studies where free ylide mechanisms were proposed to be operative. Calculations on case studies predict that the origin of metal-catalyst ‘falling off’ (dissociation) can be attributed primarily to the steric bulkiness of functional groups adjacent to the carbene carbon. </p>

Melding of Experiment and Theory Illuminates Mechanisms of Metal-Catalyzed Rearrangements: Computational Approaches and Caveats

Synthesis ◽  
2021 ◽  
Author(s):  
Dean J. Tantillo ◽  
Croix J. Laconsay
Keyword(s):  
Ligand Binding ◽  
Basis Set ◽  
Binding Modes ◽  
Dynamic Effects ◽  
Computational Tools ◽  
Paddlewheel Complexes ◽  
Sigmatropic Rearrangements ◽  
Theoretical Approaches ◽  
Theoretical Investigations ◽  
Metal Catalyzed

AbstractThis review summarizes approaches and caveats in computational modeling of transition-metal-catalyzed sigmatropic rearrangements involving carbene transfer. We highlight contemporary examples of combined synthetic and theoretical investigations that showcase the synergy achievable by integrating experiment and theory.1 Introduction2 Mechanistic Models3 Theoretical Approaches and Caveats3.1 Recommended Computational Tools3.2 Choice of Functional and Basis Set3.3 Conformations and Ligand-Binding Modes3.4 Solvation4 Synergy of Experiment and Theory – Case Studies4.1 Metal-Bound or Free Ylides?4.2 Conformations and Ligand-Binding Modes of Paddlewheel Complexes4.3 No Metal, Just Light4.4 How To ‘Cope’ with Nonstatistical Dynamic Effects5 Outlook

Transition Metal Catalyzed C–H Bond Activation by exo-metallacycle Intermediates

2021 ◽  
Author(s):  
Sumeet Sahoo ◽  
SUBHABRATA DUTTA ◽  
Shaeel Al-Thabaiti ◽  
Mohamed Mokhtar Mostafa ◽  
Debabrata Maiti
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Reaction Intermediates ◽  
Unusual Site ◽  
The Past ◽  
Site Selectivity ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Exo-metallacycles have become key reaction intermediates in activating various remote C(sp2)–H and C(sp3)–H bonds in the past decade and aided in achieving unusual site-selectivity. Various novel exo-chelating auxiliaries have assisted...

Transition metal-catalyzed [2,3]-sigmatropic rearrangements of ylides: An update of the most recent advances

Tetrahedron ◽  
2017 ◽  
Vol 73 (29) ◽  
pp. 4011-4022 ◽  
Author(s):  
Zhe Sheng ◽  
Zhikun Zhang ◽  
Changhu Chu ◽  
Yan Zhang ◽  
Jianbo Wang
Keyword(s):  
Transition Metal ◽  
Sigmatropic Rearrangements ◽  
Recent Advances ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

Chelation-assisted transition metal-catalysed C–H chalcogenylations

2020 ◽  
Vol 7 (8) ◽  
pp. 1022-1060 ◽  
Author(s):  
Wenbo Ma ◽  
Nikolaos Kaplaneris ◽  
Xinyue Fang ◽  
Linghui Gu ◽  
Ruhuai Mei ◽  
...  
Keyword(s):  
Transition Metal ◽  
Recent Advances ◽  
Site Selectivity ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

This review summarizes recent advances in C–S and C–Se formations via transition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

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