Perturbation theory of substituent effect. Importance of the field effect in transmission of the substituent effect

1980 ◽  
Vol 45 (6) ◽  
pp. 1655-1661 ◽  
Author(s):  
Robert Ponec
Keyword(s):  
Perturbation Theory ◽  
Carboxylic Acids ◽  
Quantum Chemical ◽  
Substituent Effect ◽  
Field Effect ◽  
Adequate Description ◽  
Meta Position ◽  
Unsaturated Carboxylic Acids

Various quantum chemical approaches to the problem of transmission of the substituent effect were compared. It was shown that inclusion of the electronic repulsion (field effect) was necessary to give a true picture of differences in ρ constants for reactions of the cis and trans isomers of substituted unsaturated carboxylic acids; the same holds for an adequate description of transmission of the substituent effect from the meta position on a given skeleton.

Perturbation theory of substituent effect. Quantum chemical study of the positive bridging effect

1980 ◽  
Vol 45 (7) ◽  
pp. 2054-2062 ◽  
Author(s):  
Robert Ponec
Keyword(s):  
Perturbation Theory ◽  
Quantum Chemical ◽  
Substituent Effect ◽  
Quantum Chemical Study ◽  
Reaction Medium ◽  
Chemical Study ◽  
Hammett Equation ◽  
Solvation Effects ◽  
Chemical Analogue

Mechanism of the so-called positive bridging effect was studied on the basis of an equation which can be viewed as a quantum chemical analogue of the Hammett equation. From this study it follows that the effect is presumably due to solvation effects of the reaction medium.

Perturbation theory of substituent effect. Quantum chemical estimation of the Hammet ρ constants

1980 ◽  
Vol 45 (6) ◽  
pp. 1646-1654 ◽  
Author(s):  
Robert Ponec
Keyword(s):  
Perturbation Theory ◽  
Simple Model ◽  
Quantum Chemical ◽  
Substituent Effect ◽  
Reaction Constant ◽  
Chemical Analogue

Based upon a simple model describing the substituent effect only by a change in the Coulombic integral Δαμ, a relation is derived which can be viewed as a quantum chemical analogue of the Hammet equation. This relation and knowledge of the reaction constant ρ for a reaction on a skeleton chosen as a standard make it possible to predict theoretically the magnitude of the ρ constant for this reaction on an arbitrary conjugated skeleton provided that for the latter the Hammet equation holds.

scholarly journals A solvent-dependent chirality-switchable thia-Michael addition to α,β-unsaturated carboxylic acids using a chiral multifunctional thiourea catalyst

2020 ◽  
Vol 11 (21) ◽  
pp. 5572-5576 ◽  
Author(s):  
Noboru Hayama ◽  
Yusuke Kobayashi ◽  
Eriko Sekimoto ◽  
Anna Miyazaki ◽  
Kiyofumi Inamoto ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Tertiary Amine ◽  
Michael Addition ◽  
Arylboronic Acid ◽  
Unsaturated Carboxylic Acids

An asymmetric thia-Michael addition of arylthiols to α,β-unsaturated carboxylic acids using a thiourea catalyst that bears arylboronic acid and tertiary amine moieties is reported.

Nickel-Catalyzed Decarboxylative Difluoroalkylation of α,β-Unsaturated Carboxylic Acids

2016 ◽  
Vol 55 (10) ◽  
pp. 3491-3495 ◽  
Author(s):  
Gang Li ◽  
Tao Wang ◽  
Fan Fei ◽  
Yi-Ming Su ◽  
Yan Li ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Unsaturated Carboxylic Acids
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