Electrophiles summary table

Section 12 1 On reaction with electrophilic reagents compounds that contain a ben zene ring undergo electrophilic aromatic substitution Table 12 1 m Section 12 1 and Table 12 3 m this summary give examples... 

A Summary of Substituent Effects in Aromatic Substitution A summary of the activating and directing effects of substituents in electrophilic aromatic substitution is shown in Table 16.2. 

We will give a brief summary of the general principles of diffusion and preassociation in electrophilic substitutions before discussing the values in Table 3-1 (for more comprehensive reviews see North, 1964 and Ridd, 1978). A precursor A (HN02 in... 

In summary then, the kinetics and related data are most consistent with protonated acetyl nitrate as the reagent in this medium. It is unfortunate that there is doubt as to the nature of the electrophile, as this medium combines high reactivity with good solvent properties, which has made it popular for studying substituent effects in nitration. Some relative reactivities (mostly obtained under competition conditions) are given in Table 20. 

A summary of electrophilic additions to triple bonds and allenes involving a vinyl cation is given in Table IV. 

Table 5—Summary of Electrophilic Substitution Reactions of Phenol, Diphenyl Ether, and Anisole... 

Table XXIV provides a summary of the p values for the electrophilic substitutions of thiophene derivatives when available, the p values for the corresponding reactions of benzene derivatives are also recorded for comparison.

The epoxidation of alkenes, both racemic and enantioselective, has been extensively studied in ionic liquids and Table 5.3 provides a summary of these reactions. Although no transition metal is involved, the base-catalysed epoxidation of electrophilic alkenes in ionic liquids is worth briefly mentioning. Depending on the substrate and the reaction conditions, ,/ -unsaturated carbonyl compounds were oxidised with aqueous H2O2 in [C4Ciim][BF4] or [C4Ciim][PF6] within minutes under mild conditions and no hydrolysis products were observed.120-221 The extraction of the products with scC02 instead of conventional solvents was demonstrated to be feasible, albeit on a small scale.1231... 

Table 7. Summary of some Lewis acid mediated electrophilic substitutions. ( ) Indicates the center of attack by an electrophile. ...

Table 8.1 Summary of electrophilic/nucleophile scavengers developed to date.

The chemical potential of side chains found in amino acids is limited for example, there are no efficient electron acceptors. Therefore, enzyme catalysis incorporates if necessary additional chemical potential by specific metal ions, for example, Zn2+ (see Fig. 1-6), Fe2+ Co2+, Cu2+ and others Examples are shown in Fig. 1-8 for the coordination of the transition metal ions in protein structures. Besides metal ions, cofactors or coenzymes serve to activate groups and participate in the catalytic process. A summary of cofactors and coenzymes is given in Table 1-4 the relation to vitamins is quite apparent. Chemical structures are presented in Table 1-5. Coenzymes and cofactors may act by nucleophilic or electrophilic attack on the sub-... 

Perhaps it is worth noting in summary that the series can be extended to include X=NH and X=CH2. These analogs would be expected to be even less reactive than carboxylate toward nucleophilic addition. The latter species is an enolate. We will learn in Section 7.7 that enolates are reactive nucleophiles. Carboxylate and amide anions also are nucleophilic. Even amides are somewhat nucleophilic. Going across the periodic table from F to CHj, the carbonyl substituent X transforms the carbonyl group from an electrophile to part of an nucleophilic structure in the anionic structures by increasing electron donation. 

In summary, all the early kinetic and spectroscopic evidence support the contention that the nltronlum Ion Is the effective electrophilic agent. Moreover, the rate data for the nitration reaction presented in Table I and illustrated In Figure 1 are representative of the normal reactivity pattern observed for many other electrophilic substitution reactions as shown by the results displayed in Figures 2 and 3. 

The advantages and disadvantages of fluorous solvents are represented in Table 1.3. Fluorous media have a number of potentially interesting and useful properties. They are non-protic, display neither strong Lewis acidity nor basicity, are inert to radical and oxidizing conditions, and do not react with nucleophiles or electrophiles. This general lack of reactivity is one of the keys to the successful utilization of fluorous media as common replacements for more conventional solvents. A summary of the most important physical and chemical properties of fluorous media, along with their applications, is shown in Table 1.4. 

Even without mechanistic information, one can begin to rationalize and, perhaps more importantly, predict various catalytic organopalladium reactions in consultation with Table 3 and Scheme 3. For example, the following four reactions shown in Scheme 5 are representative of the four most important types of Pd-catalyzed C—C bond formation processes discussed in detail in Parts III-VI. It is useful to note that only four patterns in Table 3, that is, (i) carbopalladation, (ii) reductive elimination, (iii) migratory insertion, and (iv) nucleophilic (or electrophilic) attack on ligands, can achieve C—C bond formation. This summary can also be appropriately modified for the formation of other types of bonds, such as C—H, C— M, C— X, and X— X bonds, where M is a metal and X is a heteroatom. 

Table 6.3 provides a summary of the common features that render a compound nucleophilic or electrophilic. 

TABLE 6.3 A SUMMARY OF COMMON NUCLEOPHILIC CENTERS AND ELECTROPHILIC CENTERS... 

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