title: Computational study on the reaction mechanism of the key thermal [4 + 4] cycloaddition reaction in the biosynthesis of epoxytwinol A.
abstract: [reaction: see text] The key [4 + 4] cycloaddition in the biosynthesis of epoxytwinol A has been established by theoretical calculations to comprise of three processes. The first step is formation of the C8-C8' bond generating a biradical intermediate. Next, rotation about the C8-C8' bond occurs, and finally the C1-C1' bond is formed. Biradicals stabilized by conjugation and two hydrogen bonds are essential for realization of this rare thermal [4 + 4] cycloaddition.
authors.affiliation: Department of Applied Chemistry, Faculty of Science, and Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan. shiina@ch.kagu.tus.ac.jp
authors.forename: Isamu
authors.initials: I
authors.lastname: Shiina
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Uchimaru
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Shoji
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kakeya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Osada
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D018360:Crystallography, X-Ray; D003500:Cyclization; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D006860:Hydrogen Bonding; D006873:Hydroquinones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
chemical_list: D004852:Epoxy Compounds; D006873:Hydroquinones; C496191:epoxytwinol A