title: Kinetic Analysis for the Multistep Profiles of Organic Reactions: Significance of the Conformational Entropy on the Rate Constants of the Claisen Rearrangement.
abstract: The significance of kinetic analysis as a tool for understanding the reactivity and selectivity of organic reactions has recently been recognized. However, conventional simulation approaches that solve rate equations numerically are not amenable to multistep reaction profiles consisting of fast and slow elementary steps. Herein, we present an efficient and robust approach for evaluating the overall rate constants of multistep reactions via the recursive contraction of the rate equations to give the overall rate constants for the products and byproducts. This new method was applied to the Claisen rearrangement of allyl vinyl ether, as well as a substituted allyl vinyl ether. Notably, the profiles of these reactions contained 23 and 84 local minima, and 66 and 278 transition states, respectively. The overall rate constant for the Claisen rearrangement of allyl vinyl ether was consistent with the experimental value. The selectivity of the Claisen rearrangement reaction has also been assessed using a substituted allyl vinyl ether. The results of this study showed that the conformational entropy in these flexible chain molecules had a substantial impact on the overall rate constants. This new method could therefore be used to estimate the overall rate constants of various other organic reactions involving flexible molecules.
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University , Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Sumiya
authors.affiliation: Graduate School of Life Science, Hokkaido University , Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nagahata
authors.affiliation: Graduate School of Life Science, Hokkaido University , Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.|Molecule and Life Nonlinear Sciences Laboratory, Research Institute for Electronic Science, Hokkaido University , Kita 20 Nishi 10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Tamiki
authors.initials: T
authors.lastname: Komatsuzaki
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University , Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Taketsugu
authors.affiliation: Department of Chemistry, Faculty of Science, Hokkaido University , Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maeda
mesh_terms: D019277:Entropy; D007700:Kinetics; D009930:Organic Chemicals / Q000737:chemistry*
chemical_list: D009930:Organic Chemicals