The E2C mechanism in elimination reactions. IX. Re-examination of the olefin-like transition-state
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The kinetics and product olefins arising from E2C-like elimination reactions of secondary bromides and tosylates having various alkyl and conjugating substituents at Cα and Cβ are re-examined in the light of the theoretical Pross-Shaik valence-bond model and the apparent lack of a β-phenyl effect. Comparison of the effect of substituents at Cα and Cβ shows that whilst there are differences in reactivity and products of E2C reactions there is also a large degree of double-bond character in the transition state. There is a good correlation between the kinetics of E2C reactions and the double-bond stabilization energy arising from both alkyl and conjugating substituents. Contributing valence-bond structures, giving asymmetry and partial charge at Cα and Cβ appear to vary in importance according to leaving group and substituent type.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Mathematical and Physical Sciences|
|Publisher:||Commonwealth Scientific and Industrial Research Organization Publishing|
|Copyright:||© 1983 CSIRO|
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