Organic chemistry nucleophilic substitution reaction

Today, we refer to the transformations taking place in Walden s cycle as nucleophilic substitution reactions because each step involves the substitution of one nucleophile (chloride ion, Cl-, or hydroxide ion, HO-) by another. Nucleophilic substitution reactions are one of the most common and versatile reaction types in organic chemistry. 

Organic halides play a fundamental role in organic chemistry. These compounds are important precursors for carbocations, carbanions, radicals, and carbenes and thus serve as an important platform for organic functional group transformations. Many classical reactions involve the reactions of organic halides. Examples of these reactions include the nucleophilic substitution reactions, elimination reactions, Grignard-type reactions, various transition-metal catalyzed coupling reactions, carbene-related cyclopropanations reactions, and radical cyclization reactions. All these reactions can be carried out in aqueous media. 

The most frequently encountered reactions in organic sulfur chemistry are nucleophilic displacement reactions. The mechanism and steric course of reactions have been the main points of interest of research groups all over the world, in particular, Andersen, Cram, Johnson, and Mislow in the United States Kobayashi and Oae in Japan Kjaer in Denmark and Fava and Montanari in Italy. The results of these investigators have been discussed exhaustively in many reviews on sulfur stereochemistry. In a recent report on nucleophilic substitution at tricoordinate sulfur, the literature was covered by Tillett (10) to the end of 1975. Therefore only some representative examples of nucleophilic substitution reactions at chiral sulfur are discussed here. However, recent results obtained in the authors laboratory are included. 

Organic chemistry and instrumental analysis Synthesis 3 Mechanisms of nucleophilic substitution reactions... 

T. Netscher, Sulfonate leaving groups for nucleophilic substitution reactions-improved structures and procedures. Recent Research Developments in Organic Chemistry, 2003, 7,71-83. 

The basic concepts of nucleophilic substitution reactions appeared in the first semester of organic chemistry. These reactions follow or Sp 2 mechanisms. (In aromatic nucleophilic substitution mechanism, we use the designation Sp Ar.) In Sfjl and Sp 2 mechanisms, a nucleophile attacks the organic species and substitutes for a leaving group. In aromatic systems, the same concepts remain applicable, but with some differences that result from the inherent stability of aromatic systems. 

With this exception we can see that the impact of the configuration mixing model on nucleophilic substitution reactions, which constitute the most widely studied organic reaction, is indeed extensive. The model readily rationalizes much available experimental data, relates the entire mechanistic spectrum within a single framework, challenges some fundamental precepts of physical organic chemistry and enables one to make reactivity predictions about reactions yet to be investigated. For such a simple, qualitative theory, this is no mean achievement. 

WALDEN INVERSION. Inversion of configuration of a chiral center m bimolecular nucleophilic substitution reactions. See also Rearrangement (Organic Chemistry),... 

Short-lived organic radicals, electron spin resonance studies of, 5, 53 Small-ring hydrocarbons, gas-phase pyrolysis of, 4, 147 Solid state, tautomerism in the, 32, 129 Solid-state chemistry, topochemical phenomena in, 15, 63 Solids, organic, electrical conduction in, 16, 159 Solutions, reactions in, entropies of activation and mechanisms, 1, 1 Solvation and protonation in strong aqueous acids, 13, 83 Solvent effects, reaction coordinates, and reorganization energies on nucleophilic substitution reactions in aqueous solution, 38, 161 Solvent, protic and dipolar aprotic, rates of bimolecular substitution-reactions in,... 

Nucleophilic substitution reactions are among the first synthetic transformations introduced to beginners learning organic chemistry. The mechanisms for these... 

The reason we ve discussed nucleophilic substitution reactions in such detail is that they re so important in organic chemistry. In fact, we ve already seen a number of substitution reactions in previous chapters, although they weren t identified as such at the time. For example, we said in Section 8.9 that acetylide anions react well with primary alkyl halides to provide the alkyne product. 

The replacement of an alcoholic hydroxyl group by a halogen atom is one of the most common reactions carried out in organic chemistry. The usual reagents for effecting the transformation include halogen acids, thionyl chloride, and phosphorus halides. The reaction is of particular theoretical interest since experiments with optically active alcohols suggest still another substitution process. It has been called an internal nucleophilic substitution reaction (S i).20... 

Nucleophilic substitution reactions by solvolysis at a carbon atom with a leaving group, Eq. (1), are well enough understood that they are often used in introductory organic chemistry textbooks as an instructional foundation for mechanistic concepts. Information on how variables such as the structure, stereochemistry, the leaving group (LG), and the nucleophilicity of the solvent (SOH) control the reactivity is so extensive that prediction of results for new cases can be made with considerable confidence. 

In organic sulfur chemistry, these decet species have long been considered to be transition states or unstable intermediates in the nucleophilic substitution reaction (SN2), and not to exist as real molecules except in a few cases [13]. However, recently numerous heteroatom compounds containing hypervalent structures have proved to be of considerable interest to many organic chemists. 

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