title: Thermal degradation of methyl beta-D-glucoside. a theoretical study of plausible reaction mechanisms.
abstract: Thermal conversion of methyl beta-d-glucoside to levoglucosan was studied with the MP4//DFT(B3LYP) method. The first step is conformational change of the reactant to (1)C(4) from (4)C(1). The second step is intramolecular nucleophilic substitution at the anomeric C1, which occurs via one step without oxacarbenium ion intermediate. The DeltaG(0)() value (52.5 kcal/mol) is smaller than the C1-O1 bond energy, indicating the direct homolysis mechanism is clearly ruled out. Bimolecular reaction also occurs with smaller activation energy via the similar transition state.
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hosoya
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Nakao
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sato
authors.forename: Haruo
authors.initials: H
authors.lastname: Kawamoto
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Sakaki