Nucleophiles basic principles

After a decade of research the basic principles in the chemistry of decamethylsilicocene (1) seem to be understood. This compound shows the reactivity of a nucleophilic silylene due to the fact that the Tt-bonded pentamethylcyclopentadienyl ligands are easily transferred to a-bonded substituents during the reaction. The steric requirements of these substituents permit reactions with bulky substrates. The migratory aptitude and the leaving-group character of the pentamethylcyclopentadienyl groups... 

In this chapter, the basic principle of arrow pushing was introduced in the context of organic reactions driven by homolytic cleavage, heterolytic cleavage, or concerted mechanisms. Furthermore, the concept of polarity was introduced using heteroatoms and common organic functional groups. This discussion led to the definitions of nucleophiles and... 

The basic principle of this chemistry is that rf-alkene-Pd(II) complexes, usually generated in situ, are easily attacked by nucleophiles to form (T-alkyl-Pd species, which in turn are able to react further in a variety of ways. In general, several kinds of nucleophiles (e.g. alcohols, amines and enolethers) are able to attack the alkene complex intermediates in an intra- or intermolecular fashion. This article, however, focusses exclusively on intramolecular alkoxypalladations, i.e. transformations of the type 2 3, which are of particular synthetic relevance. 

On the other hand, however, these two areas of cationic polymerization are not completely separated fields. In spite of the differences, both processes proceed on electron-deficient active species cations or species with a partial positive charge. Thus, propagation in both cases involves attack of the nucleophile (double bond or heteroatom) on electrophilic active centers. Several basic principles will therefore hold for both vinyl and ring-opening cationic polymerization. 

The basic principles governing nucleophilicity, such as the steric effects making primary OH groups more nucleophilic than secondary OH groups, or, in a... 

In the following discussion nucleophilic reactions with LL substrate will be analyzed by making use of basic principles of electronic states. We will show that (a) under certain circumstances the transition state of nucleophilic reactions must be diradicaloid and (b) the diradicaloid nature of the transition state will in general increase with the increase in the electrophilicity of the substrate. 

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. 

Nucleophilic addition to the C-O double bond of carbonyl derivatives is one of the most widely used C-C-bond forming reactions in organic synthesis. The synthetic value of this process lies particularly on the stereocontrolled formation of a new C-O-chiral center when aldehydes or ketones are used. On the other hand, carbonyl derivatives themselves can serve as nucleophiles leading to new carbon-carbon bonds and thus expanding the synthetic scope of these functional groups. The explanation of the underlying basic principles in terms of reactivity and stereochemical models is beyond the scope of this book and will not be discussed in the following chapter since many textbooks cover these issues. Instead, we wish to provide the practitioner with examples that detail the delicate relationship of an individual, unique structure with its special reactivity delineated thereof... 

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 ... 

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