Substituent effects. XX. Highly electron-deficient carbocation solvolyses.
スポンサーリンク
概要
- 論文の詳細を見る
The solvolysis rates of 1-aryl-2,2,2-trifluoroethyl tosylates (<B>1</B>-OTs) and <I>m</I>-nitrobenzenesulfonates (<B>1</B>-ONs) were determined conductometrically in aqueous ethanol and aqueous TFE. While the Brown ρ<SUP>+</SUP>σ<SUP>+</SUP> equation does not give a simple linear plots, but a remarkably split pattern, there is a linear free energy relationship between the solvolyses of <B>1</B>-OTs and 1-aryl-1-(trifluoromethyl)ethyl tosylates (<B>2</B>) with a slope of unity over a wide range (10<SUP>8</SUP> in reactivity) of substituents from <I>p</I>-MeO to unsubstituted derivatives. The substituent effect on the solvolysis of <B>1</B> should be closer to that on the solvolysis of <B>2</B>, rather than to the σ<SUP>+</SUP> substituent effect. The ρ value for this system was estimated to be identical to the value of −6.3 assigned for <B>2</B>, and the <I>r</I> value in the LArSR correlation to be comparable with or even higher than the <I>r</I>=1.4 of <B>2</B>. The enhanced <I>r</I> value of this system must be caused from a strong destabilization of the transition state by the α-CF<SUB>3</SUB> substituent. Extremely high ρ<SUP>+</SUP> values have recently been pointed out for many solvolyses generating highly electron-deficient carbocations; however, in no case is the ρ<SUP>+</SUP> value equally high for the electron-attracting region of the substituent. In fact, they all resulted in significantly concave σ<SUP>+</SUP> plots, suggesting a mechanistic transition. All of the conflicts must be attributed to the inadequacy of the simple application of σ<SUP>+</SUP>. The use of the Brown σ<SUP>+</SUP> scale must be the only cause of a curve break in the correlation plot of such a system having a significantly different resonance demand.
- 公益社団法人 日本化学会の論文
著者
-
Fujiyama Ryoji
Department Of Material Science Faculty Of Science Kochi University
-
Mishima Masaaki
Department Of Chemistry And Physics Of Condensed Matter Graduate School Of Sciences Kyushu Universit
-
FUJIO Mizue
Department of Chemistry, Faculty of Science, Kyushu University
-
Tsuno Yuho
Department Of Chemistry Faculty Of General Education Kumamoto University
-
Sakaguchi Shin-ichi
Department of Chemistry, Faculty of Science, Kyushu University
-
Murata Akihisa
Department of Chemistry, Faculty of Science, Kyushu University
-
Fujiyama Ryoji
Department of Chemistry, Faculty of Science, Kochi University
関連論文
- Solvent Effects on Anchimerically Assisted Solvolyses. III.^ Solvent Effects on the Solvolyses of (1-Arylcycloalkyl)methyl p-Toluenesulfonates
- CARBON-13 NMR STUDIES ON REACTION MECHANISMS (V) : SALT EFFECTS ON ACETOLYSIS OF 2-(p-ANISYL)ETHYL TOSHYLATE
- Thermodynamic Stabilities and Resonance Demand of Aromatic Radical Anions in the Gas Phase
- The β-Silicon Effect : III. Substituent Effects of the β-Si-Aryl Moiety in the Solvolysis of 1-Aryl-2-(aryldimethylsilyl)ethyl 3,5-Dinitrobenzoates
- The β-Silicon Effect. II. Substituent Effects on the Solvolysis of 1-Aryl-2-(aryldimethylsilyl)ethyl 3,5-Dinitrobenzoates
- The γ-Silicon Effect. II. The Substituent Effect on the Solvolysis of 3-(Aryldimethylsilyl)-2,2-dimethylpropyl p-Bromobenzenesulfonates
- The γ-Silicon Effect. I. Solvent Effects on the Solvolyses of 2,2-Dimethyl-3-(trimethylsilyl) propyl and 3-(Aryldimethylsilyl)-2,2-dimethylpropyl ρ-Toluenesulfonates
- A Quatitative Scale for the Structural Effect on Reactivity toward Nucleophilic Displacement at Silicon
- Pyrolytic Elimination of 1-Ary1-2-(trimethylsilyl)ethyl Acetates via Two Distinct Pathways
- Substituent Effects in the 1,1-Diphenylcarbenium Systems : Hydration and Bromination of 1,1-Diphenylethylenes
- Non Linearity and Non-Additivity of Substituent Effects in Solvolysis of 1, 1-Diphenylethyl p-Nitrobenzoates
- Theγ-Silicon Effect. IV.^1 The Solvolysis Mechanism of 3-(Aryldimethylsilyl)propyl p-Toluenesulfonates
- Substituent Effects on the Solvolysis Rates and Gas Phase Stabilities of 1,2,2-Trimethyl-1-phenylpropyl and 1,2,2-Trimethyl-1-(2-methylphenyl)propyl Systems
- Thermodynamic Stabilities of Phenonium Ions Based on Bromide-Transfer Equilibria in the Gas Phase^
- Substituent Effects on the Solvolysis of 2, 2, 2-Trifluoro-1, 1-diphenylethyl Tosylates. II. ^ 3-Chlorophenyl-and 3, 5-Dichlorophenyl-Fixed Systems
- Substituent Effects on the Solvolysis of 1,1-Diphenyl-2,2,2-trifluoroethyl Tosylates: Comparison between Symmetrically Disubstituted and Monosubstituted Systems
- Gas-Phase Substituent Effects in Highly Electron-DeGFicient Systems. II. Stabilities of 1 -Aryl-2, 2, 2-trifluoroethyl Cations Based on Chloride-Transfer Equilibria^
- Resonance Effects in the Solvolysis of α-τ-Butyl-α-.neopentylbenzyl and α-τ-Butyl-α-isopropylbenzyl ρ-Nitrobenzoates
- Gas-Phase Substituent Effects in Higbly Electron-Deficient Systems. I. Intrinsic Stabilities of 1-Aryl-1-(trifluoromethyl)ethyl Cations^
- Changes of the Aromatic Character of the Ring in Exocyclically Substituted Derivatives of Benzylic Cation as a Result of Varying Charge at the exo-Carbon Atom
- Gas-Phase Substituent Effects in Stabilized Benzylic Carbocations. Basicities of Benzaldehydes, Acetophenones, and Methyl Benzoates in the Gas Phase^
- Prediction of gas-particle dynamics and heat transfer in a two-dimensional spouted bed
- The Effect of Temperature on the Minimum Fluidization Velocity Calculated by Distinct Element Method
- Kinetic Isotope Effects for Addition of Lithium Pinacolone Enolate to Benzaldehyde
- Synthesis of (S)-Ketamine via [1,3]-Chirality Transfer of a Stereocenter Created by Enantioselective Aldol Reaction
- SUBSTITUENT EFFECTS ON THE SOLBOLYSIS OF 1-ARYL-1-(TRIFLUOROMETHYL) ETHYL TOSYLATES
- Gas Phase Basicities of α-Trimethylsilylstyrenes. Intrinsic Effect of α-Trimethylsilyl Group on the Stability of Carbenium Ions
- GAS PHASE SUBSTITUENT EFFECT ON BASICITY OF PHENYLACETYLENE : INTRINSIC RESONANCE DEMAND OF A VINYLIC CATION
- Substituent Effect on the Gas Phase Basicity of Pyridine N-Oxide
- Substituent Effect on the Gas Phase Basicity of α-t-Butylstyrene. Coplanarity and Resonance Demand of a Benzylic Carbocation
- Gas-Phase Lithium Cation Basicities of Acetophenones : A Linear Relationship between Lithium Cation and Proton Basicities
- Gas Phase Substituent Effect on Basicity of Phenylacetylene. Intrinsic Resonance Demand of Phenylvinyl Cation
- Stability of Complexes of Phenylacetylides and Benzyl Alkoxides with Methanol in the Gas Phase. Acid-Base Correlation in the Ionic Hydrogen-Bond Strength
- Substituent Effect on Electron Affinity of 2,6-Dimethylnitrobenzene
- Effect of the Twisted Nitro Group on Gas Phase Acidities of Phenol, toluene, Aniline, and Benzoic Acid. Steric Inhibition of Intrinsic Resonance Effect
- Gas Phase Basicities of Styrenes toward Trimethylsilyl Cation. Structure and Stability of Me_3Si-Styrene^+ Complexes
- Gas Phase Basicities of Acetophenones toward Trimethylsilyl Cation
- SUBSTITUENT EFFECTS ON THE HIGHLY ELECTRON-DEFICIENT CARBOCATION SOLVOLYSES
- Silicon Effects. III. Rates and Products for Solvolysis of .ALPHA.-(Pentamethyldisilanyl)benzyl Halides and 1,1,2,2-Tetramethyl-1,2-disilaindan-3-yl Chloride. Structure and Stability of .ALPHA.-(Pentamethyldisilanyl)benzyl Cation in Solution.
- Substituent effects. XXI. Solvolysis of benzyl tosylates.
- Substituent effects. XVIII. The resonance demand in the acetolysis of neophyl brosylates.
- Substituent effects. XX. Highly electron-deficient carbocation solvolyses.
- Substituent effects. 22. The solvolysis of .ALPHA.-t-butylbenzyl tosylates.
- Substituent effects. XIX. Solvolysis of 1-aryl-1-(trifluoromethyl)ethyl tosylates.
- Photolysis of alcohols and alkanones in acetone solutions. Photochemical [2+2]cycloaddition reaction between acetone and aliphatic enols.
- The Substituent Effect. VI. Inductive and π-Electronic Effects in the Phenol Hydroxyl Chemical Shifts in DMSO
- The Substituent Effect. V. NMR Chemical Shifts of Hydrogen-bonding Hydroxyl Proton of Phenols in DMSO
- Photochemical decarbonylation of (.ALPHA.-arylacyl)triphenylgermane.
- Substituent effects on 15N and 17O NMR chemical shifts in 4'-substituted trans-NNO-azoxybenzenes.
- Silicon Effects. II. Structure and Stability of 1-Phenyl-2-(trimethylsilyl)ethyl Cation in Solution.
- Synthesis of 2,2-diphenyl-3-oxetanol derivatives and their thermal or acid-catalyzed decomposition.