Nucleophilic substitution basic principles

In principle, any compound with a lone pair can act as either a base or a nucleophile toward C(sp3)-X, causing either E2 elimination or Sn2 substitution to occur. It is possible to predict whether substitution or elimination will occur with moderate accuracy (Table 2.1). Two factors largely determine the course of the reaction (1) the nucleophilicity and basicity of the lone-pair-bearing compound, and (2) the identity of the substrate Me or Bn, 1°, 2°, or 3° halide. 

Substitution and Addition Reactions. All types of reactions between inorganic anions and organic partners can be executed under the PTC conditions. Nucleophilic aliphatic substitution in alkyl halides with cyanide anions to form nitriles was presented in the Introduction as a typical example of PTC on which the basic principles and characteristic features of this catalysis were discussed. 

The functional group transformations are derived from either electrophilic aromatic substitution or nucleophilic aromatic substitution reactions. The electrophilic aromatic substitution functional group transform is shown with a simple X group, where X is chlorine, bromine, nitro, or sulfonyl. The reagents are different, but the basic principle for the formation of such compounds is the same. 

In Chapter 9, we introduced the basic principles of nucleophilic substitution and elimination reactions. We focused almost entirely upon the reactions of haloalkanes and alcohols. In this chapter, we will expand upon these reactions and consider a much wider range of nucleophiles, leaving groups, substrates, solvents, and their effects on nucleophilic substitution and elimination reactions. We will ask ... 

Early evidence for the HSAB Principle came from studies of nucleophilic reactivity series towards different substrates, or electrophiles. " Some electrophiles, such as H+, in proton transfer reactions or CH3CO substitution reactions of esters, reacted rapidly with bases that were strong bases towards the proton. Other electrophiles, such as Pt(II) or RO+, reacted rapidly with polarizable bases, and were indifferent to proton basicity. 

The material is presented according to the mechanistic types nucleophilic and electrophilic substitution, addition reactions, radical, pericyclic, proton and electron transfer reactions. Orbital and electrostatic models are used for structural correlations of interacting molecular systems along the reaction paths. Particular attention is focussed on the characteristics of the transition state. The text combines phenomenology with the basic theoretical principles needed to understand and predict chemical reactivity. 

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