title: Asymmetric Total Synthesis of Indole Alkaloids Containing an Indoline Spiroaminal Framework.
abstract: The total synthesis of the indole alkaloids, neoxaline, oxaline and meleagrin A, all containing a unique indoline spiroaminal framework, was accomplished through the stereoselective introduction of a reverse prenyl group to the congested benzylic carbon of furoindoline, a two-pot transformation of indoline (containing three nitrogen atoms at appropriate positions) to the featured indoline spiroaminal framework, and elimination of carbonate assisted by the adjacent imidazole moiety to construct the (E)-dehydrohistidine. The absolute stereochemistry of neoxaline was elucidated through our total synthesis. In addition, we evaluated the bioactivity, especially the anti-infectious properties, of neoxaline and oxaline, and of some synthetic intermediates.
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).|Graduate School of Infection Control Sciences, Kitasato University (Japan).
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Graduate School of Infection Control Sciences, Kitasato University (Japan).
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ideguchi-Matsushita
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).|Graduate School of Infection Control Sciences, Kitasato University (Japan).
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Hirose
authors.affiliation: School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641 (Japan).
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shirahata
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).
authors.forename: Rei
authors.initials: R
authors.lastname: Hokari
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).
authors.forename: Aki
authors.initials: A
authors.lastname: Ishiyama
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).|Graduate School of Infection Control Sciences, Kitasato University (Japan).
authors.forename: Masato
authors.initials: M
authors.lastname: Iwatsuki
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).|Graduate School of Infection Control Sciences, Kitasato University (Japan).
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sugawara
authors.affiliation: School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641 (Japan).
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan).
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Otoguro
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan). omuras@insti.kitasato-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ōmura
authors.affiliation: Kitasato Institute for Life Sciences, Kitasato University (Japan). sunazuka@lisci.kitasato-u.ac.jp.|Graduate School of Infection Control Sciences, Kitasato University (Japan). sunazuka@lisci.kitasato-u.ac.jp.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Sunazuka
keywords: alkaloids; fused-ring systems; natural products; spiro compounds; total synthesis