title: Ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes with amines: rapid access to 2-substituted 4-hydroxyindole.
abstract: An efficient ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes with primary amines has been developed. The reaction proceeded at room temperature without any additives to provide 2-substituted tetrahydroindol-4-ones in good to excellent yields without the formation of the 3-substituted isomers. The obtained product was readily converted into a 2-substituted 4-hydroxyindole derivative via a synthetically useful indoline intermediate.
authors.affiliation: Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Sugitani, Toyama 930-0194, Japan.
authors.forename: Hisanori
authors.initials: H
authors.lastname: Nambu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukumoto
authors.forename: Wataru
authors.initials: W
authors.lastname: Hirota
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yakura
mesh_terms: D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D003510:Cyclohexanes / Q000737:chemistry*; D003521:Cyclopropanes / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D003510:Cyclohexanes; D003521:Cyclopropanes; D007211:Indoles; D013141:Spiro Compounds; C510548:4-hydroxyindole; C506365:Cyclohexane