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Ingold elimination reactions

Other terms that he invented include the system of classification for mechanisms of aromatic and aliphatic substitution and elimination reactions, designated SN1, SN2, El, and E2. "S" and "E" refer to substitution and elimination, respectively, "N" to nucleophilic, and "1" and "2" to "molecularity," or the number of molecules involved in a reaction step (not kinetic order, having to do with the equation for reaction rate and the concentration of reactants). Ingold first introduced some of these ideas in 1928 in a... [Pg.234]

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. [Pg.237]

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. [Pg.43]

A rel = 1.2 x 10 6) (Ingold, 1957). Neopentyl halides are known in fact to be extremely stable towards nucleophilic displacement. There are few examples in the gas phase that allow for a full comparison since alkyl halides with P-hydrogens may be prone to undergo elimination reactions simultaneously with displacement. For example, the reaction of F with C2H5C1 proceeds with a rate constant krel = 0.86, compared to that of CH3C1 (Jose, 1976), whereas (CH3)3CCH2C1 reacts with k[cl = 0.61 (Olmstead and Brauman,... [Pg.210]

Ingold (1) has mentioned that the older literature contains several observations indicating the existence of stereochemically favorable and unfavorable situations for elimination reactions leading to acetylenic compounds. For instance, Michael (2) found that chlorofumaric acid (4) is converted by alkali about 50 times faster than in chloromaleic acid (5) into acetylene dicarboxylic acid (6). Chovanne (3) has observed that cis-dichloroethylene (7) is transformed by alkali about 20 times faster than is the trans-isomer 8 into chloroacetylene (9). [Pg.348]

Trans-elimination is therefore clearly stereochemically favored over cis-elimination indicating that stereoelectronic effects must play a decisive role in these reactions. Ingold (1) has pointed out that ... [Pg.349]

The basic decomposition of tetraalkylammonium salts (the Hofmann degradation), has been reviewed extensively so.135) and will not be discussed here in detail. However, it should be noted that both displacement reactions and a-proton abstraction reactions may occur in addition to elimination reaction 30>. Ingold and Patel 75> report that the amount of substitution relative to elimination varies depending upon both the substituent on nitrogen and the base. [Pg.112]

Another interesting comparison was reported by von Braun 150> in which various quaternary ammonium hydroxides were decomposed under Hofmann conditions and in the presence of glycerol. These results also show that the displacement reaction is favored in the presence of a hydroxylic solvent. It was also noted by Hanhart and Ingold 57> that displacement reactions are favored over elimination reactions in thermal decompositions of quaternary ammonium salts as the nucleophilicity of the anion is increased from chloride to acetate. [Pg.113]

Hughes, E. D., and K. I. Juriyan Influence of Poles and Polar Linkings on the Course pursued by Elimination Reactions. Part XXII. Stable Derivates of the Tercovalent-carbon Compounds of Ingold and Jessop. J. Chem. Soc. (London) (1935) 609. [Pg.50]

Hughes and Ingold, primarily studying substitution and elimination reactions, have extensively investigated the effect of molecular solvents on reactions passing through dipolar-transition states [2]. On the basis of a simple qualitative solvation model, which exclusively considers electrostatic interactions between ions (or dipolar molecules) and solvent molecules in initial and transition states it is generally... [Pg.274]

Cooper, K.A., Dhar, M.L., Hughes, E.D., Ingold, C.K., MacNulty, B.J. and Woolf, L.I., Mechanism of elimination reactions. Part VII. Solvent effects on rates and product-proportions in uni- and bi-molecular substitution and elimination reactions of allq l halides and sulphonium salts in hydroxylic solvents, J. Chem. Soc. 2043-2049 (1948). [Pg.303]

At about the same time as his studies of the mechanisms of elimination reactions. Sir Christopher Ingold and his collaborator Edward D. Hughes applied the tools of kinetics and stereochemistry to nucleophilic substitution. [Pg.310]

Ingold, C. K. Vass, C. C. N. (1928). The influence of poles and polar linkings on the course pursued by elimination reactions 11. The mechanism of exhaustive methylation. Journal of the Chemical Society, 3125-3127, ISSN 0368-1769 Janus, E. Stefaniak, W. (2008). The Diels-Alder reaction in phosphonium ionic liquid catalysed by metal chlorides, tiiflates and triflimides. Catalysis Letters, 124,1-2,105-110, ISSN 1011-372X... [Pg.674]


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See also in sourсe #XX -- [ Pg.600 ]




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