Claisen rearrangements of benzyl vinyl ethers: theoretical investigation of mechanism, substituent effects, and regioselectivity

2017 ◽  
Vol 15 (37) ◽  
pp. 7887-7893 ◽  
Author(s):  
Elizabeth H. Krenske ◽  
Jed M. Burns ◽  
Ross P. McGeary
Keyword(s):  
Theoretical Investigation ◽  
Theoretical Calculations ◽  
Substituent Effects ◽  
Vinyl Ethers ◽  
Claisen Rearrangements

Theoretical calculations are reported which examine the mechanisms of Claisen rearrangements of benzyl vinyl ethers and the ways in which substituents influence reactivity and regioselectivity.

scholarly journals Substituent Effects on EI-MS Fragmentation Patterns of 5-Allyloxy-1-aryl-tetrazoles and 4-Allyl-1-aryl-tetrazole-5-ones; Correlation with UV-Induced Fragmentation Channels

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3282
Author(s):  
Alina Secrieru ◽  
Rabah Oumeddour ◽  
Maria L. S. Cristiano
Keyword(s):  
Theoretical Calculations ◽  
Substituent Effects ◽  
Radical Cations ◽  
Electronic Effects ◽  
Diverse Range ◽  
The Matrix ◽  
Electron Impact Mass ◽  
Fragmentation Patterns ◽  
Tetrazole Derivatives ◽  
Impact Mass

1,4- and 1,5-disubstituted tetrazoles possess enriched structures and versatile chemistry, representing a challenge for chemists. In the present work, we unravel the fragmentation patterns of a chemically diverse range of 5-allyloxy-1-aryl-tetrazoles and 4-allyl-1-aryl-tetrazolole-5-ones when subjected to electron impact mass spectrometry (EI-MS) and investigate the correlation with the UV-induced fragmentation channels of the matrix-isolated tetrazole derivatives. Our results indicate that the fragmentation pathways of the selected tetrazoles in EI-MS are highly influenced by the electronic effects induced by substitution. Multiple pathways can be envisaged to explain the mechanisms of fragmentation, frequently awarding common final species, namely arylisocyanate, arylazide, arylnitrene, isocyanic acid and hydrogen azide radical cations, as well as allyl/aryl cations. The identified fragments are consistent with those found in previous investigations concerning the photochemical stability of the same class of molecules. This parallelism showcases a similarity in the behaviour of tetrazoles under EI-MS and UV-irradiation in the inert environment of cryogenic matrices of noble gases, providing efficient tools for reactivity predictions, whether for analytical ends or more in-depth studies. Theoretical calculations provide complementary information to articulate predictions of resulting products.

Naked diazaborepin dyes: Synthesis, photophysical properties, substituent effects and theoretical calculations on ESIPT process

2020 ◽  
Vol 175 ◽  
pp. 108128
Author(s):  
Nuonuo Zhang ◽  
Genjiang Liu ◽  
Jiaying Yan ◽  
Tingting Zhang ◽  
Xiang Liu
Keyword(s):  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Substituent Effects

scholarly journals Reverse Cope Elimination of Hydroxylamines and Alkenes or Alkynes: Theoretical Investigation of Tether Length and Substituent Effects

2012 ◽  
Vol 134 (4) ◽  
pp. 2434-2441 ◽  
Author(s):  
Elizabeth H. Krenske ◽  
Edwin C. Davison ◽  
Ian T. Forbes ◽  
Jacqueline A. Warner ◽  
Adrian L. Smith ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Substituent Effects

Mindo-Forces Study on the Keto-Enol Tautomerism of α-Substituted Acetaldehydes XCH2CH=O (X = H, F, Oh, Cn, NH2, NO2, CH3, CF3, OCH3): Comparison with Acetyl Derivatives

2004 ◽  
Vol 59 (12) ◽  
pp. 980-986
Author(s):  
Wasim F. Al-Halasah ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Substituent Effects ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Electron Densities ◽  
The Stability ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on α- substituted acetaldehydes XCH2CH=O and their enols (X = H, F, OH, CN, NH2, NO2, CH3, CF3, OCH3). All substituents were found to decrease the stability of the acetaldehyde and mostly in the case of electron withdrawing capacity (e. g NO2 and CF3). This agrees with theoretical calculations, except in the case of F. The substituent effects on the stabilities in this study are compared with results obtained from our previous theoretical calculations on acetyl derivatives. Geometrical parameters, electron densities, and Gibbs free energies are reported.

Investigation of quantitative structure–reactivity relationships in the aliphatic Claisen rearrangement of bis-vinyl ethers reveals a dipolar, dissociative mechanism

2014 ◽  
Vol 12 (8) ◽  
pp. 1292-1308 ◽  
Author(s):  
Natasha F. O'Rourke ◽  
Jeremy E. Wulff
Keyword(s):  
Vinyl Ether ◽  
Claisen Rearrangement ◽  
Substituent Effects ◽  
Quantitative Structure ◽  
Vinyl Ethers ◽  
Dissociative Mechanism ◽  
Mechanism Of Reaction ◽  
Kinetic Investigations

Kinetic investigations of substituent effects in the Claisen rearrangement of bis-vinyl ether substrates suggest a dissociative mechanism of reaction.

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