An Ab Initio Study of SN2 Reactivity at C6 in Hexopyranose Derivatives. II. Role of Populations, Barriers, and Reaction Path Curvature
This paper continues our investigation into a simple dipole-dipole interaction model proposed to explain the dramatically reduced SN2. reactivity at the primary C6 position of galacto-configured pyranose systems relative to their gluco isomers. We present ab initio calculations (B3LYP/6-31+G(d,p)) on six model structures that show that this effect is not a major influence. Reactant rotameric equilibria as well as free-energy reaction barriers and reaction path curvature were evaluated. Results point to a number of other factors that could account for the observed reactivity differences. Our results cast doubt on the general relevance of transition structure dipole-dipole repulsions to SN2 reactivity.
R. Dawes et al., "An Ab Initio Study of SN2 Reactivity at C6 in Hexopyranose Derivatives. II. Role of Populations, Barriers, and Reaction Path Curvature," Journal of Physical Chemistry A, vol. 109, no. 1, pp. 218-223, American Chemical Society (ACS), Jan 2005.
The definitive version is available at http://dx.doi.org/10.1021/jp0372901
Keywords and Phrases
Dipole-dipole interactions; Galacto-configurations; Hexopyranose derivatives; Tetrahydropyran model structures, Carbohydrates; Chemical reactions; Electrostatics; Free energy; Mathematical models; Negative ions; Stereochemistry, Derivatives, carbohydrate; carbon, article; chemical structure; chemistry; computer simulation; thermodynamics, Carbohydrates; Carbon; Computer Simulation; Models, Molecular; Molecular Structure; Thermodynamics
International Standard Serial Number (ISSN)
Article - Journal
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