6533b870fe1ef96bd12cf06e

RESEARCH PRODUCT

Experimental and theoretical study of stereoelectronic and H-bond control of reactivity in α- and β-methyl d-glucopyranoside ozonolysis

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Abstract The topography of the molecular electrostatic potential (MEP) of α and β anomers of methyl d -glucopyranosides has been used to analyze the reactivity of these species towards electrophilic attack and to complete the results we obtained during the ozonation reaction. Molecular mechanics (MM) and molecular dynamics (MD) simulations have been performed to screen the conformational space of α- and β-methyl d -glucopyranosides in order to determine the chair conformations which correspond to a global minimum energy conformation. Density Functional Theory (DFT) (Faststructure) and PM3 (semiempirical) calculations have been carried out to refine the geometries of the 4 C 1 and 1 C 4 chair conformations of both anomers. The MEPs of the α and β anomers in their 4 C 1 chair conformations have been determined by DFT calculations and have been used to predict their respective reactivities. The good agreement between predicted and experimental results observed in organic solutions compared with those performed in aqueous solutions indicates that the water molecules play an “active” role in modifying the intramolecular H-bonds which control the MEP topography and consequently the chemical reactivity of both anomers in solutions.