Mechanisms of -Elimination

For reviews, see E. Baeiocehi in Chemistry of Halides, Pseudo-HaUdes and Azides, Part 2, S. Patai and Z. Kappopjit, eds., John Wiley Sons, New York, 1983, Chapter 23 W. H. Saunders, Jr., and A. F. Coekerill, Mechanisms of Elimination Reactions, John Wiley Sons, New York, 1973 D. J. McLennan, Tetrahedron 31 2999 (1975). 

W. H. Saunders, Jr., and A. F. Cockerill, Mechanisms of Elimination Reactions, John Wiley Sons, New Vbik, 1973. 

From the thorough studies of the mechanism of elimination of hydrogen halides from vicinal fluorohalo compounds, it follows that the result of elimination depends on the stabihty of the carbanionic species in which the negative charge is on the carbon P to fluorine and a to chlorine or bromine [43, 44, 45, 46, 47, 48, 49, 50, 51. 52, 53, 54]... 

In the course of work on the mechanism of elimination reactions, the author and his co-workers have measured reaction-rate constants for the second-order elimination of hydrogen chloride from six dichloroethyl compounds of type Ar2CHCHCl2 and three monochloroethyl compounds of type Ar2CHCH2Cl (7). Samples of each of these materials were furnished to the Bureau of Entomology and Plant Quarantine for insecticidal testing, and the author is indebted to C. C. Deonier and I. H. Gilbert for permission to use certain of their data in this paper. The rate constants and larvicidal results are given in Table I. 

Saunders, W.H. and Cockerill, A.F. (1973). Mechanisms of Elimination Reactions, Wiley, New York... 

K. A. Cooper, E. D. Hughes, and C. K. Ingold, "The Mechanism of Elimination Reactions. Part III. Unimolecular Olefin Formation from Tert.-Butyl Halides in Acid and Alkaline Aqueous Solutions," JCS 140 (1937) 1280. 

Mechanism of Elimination Reactions. PartX. Kinetics of Olefin... 

Kaldor, S.B., Eredenburg, M.E. and Saunders, W.H. (1980). Mechanisms of elimination reactions 32. Tritium isotope effects and tunnel effects in the reaction of 2,2-diphenylethyl-2-t derivatives with various bases. J. Am. Chem. Soc. 102, 6296-6299... 

Studies of structure effects on rate have helped substantially to bring researchers to the present deep understanding (72,13) of the mechanism of elimination reactions. Beside stereochemical evidence, successful linear correlations have yielded the desired information. The published series of reactants and correlations are summarized in Table II. The fit of straight lines to experimental data is usually good or very good, and only a few points deviate significantly. Details of the correlations may be found in the original literature here we will concentrate on the values of the slopes. 

The study of heterogeneous catalysis with the emphasis on the effects of reactant structure stimulates consideration of the reacting system in terms of mutual interactions. Modification of the catalyst surface by the action of reactants is a part of these interactions. This idea is not new, but hitherto little evidence supported it now it is an inherent component of the accepted mechanism of elimination reactions. In general, the working surface may be quite different from the initial surface. Even the solvent may participate in the mechanism, as the results of the Delft school (125, 161, 162) indicate, by temporally accommodating hydrogen species formed in a reaction step from the reactants or hydrogen molecules on the surface. 

Going over the basics and mechanisms of nucleophilic substitution reactions Mastering mechanisms of elimination/addition reactions Determining synthesis strategies for aromatic systems... 

Hughes, E. D., C. K. Ingold, and V. J. Shiner jr. Mechanism of elimination reactions. Part XVII. The comparative unimportance of steric strain in unimolecular olefin elimination. J. chem. Soc. [London] 7953, 3827. 

Methanol can be absorbed through the skin or from the respiratory or gastrointestinal tract and is then distributed in body water. The primary mechanism of elimination of methanol in humans is by oxidation to formaldehyde, formic acid, and C02 (Figure 23-3). 

For discussion, see Saunders Cockerill Mechanisms of Elimination Reactions , Wiley New York. 1973, pp. 548 554. 

In discussing the mechanism of eliminations over solids, the nomenclature which has been developed for homogeneous reactions will be used. Therefore the basic mechanisms of olefin formation have first to be outlined and their meaning in heterogeneous catalysis defined. 

These considerations indicate that the nature of Ri and R2 is an important factor in determining the alkaline lability of the O-glycosidic bond. / -Elimination usually occurs most readily when there are no free amino or carboxyl groups on the serine or threonine residue to which the glycosyl is attached. When both functional groups are unsubstituted / -elimination does not occur (I, II, IX). The N-2,4-dinitrophenyl derivatives of Vercellotti et al. represent an extreme case, possibly involving a different mechanism of / -elimination. 

---