title: Oxidative Dearomatization of 4,5,6,7-Tetrahydro-1H-indoles Obtained by Metal- and Solvent-Free Thermal 5-endo-dig Cyclization: The Route to Erythrina and Lycorine Alkaloids.
abstract: A facile one-pot approach based on a thermally induced metal- and solvent-free 5-endo-dig cyclization reaction of the amino propargylic alcohols in combination with Dess-Martin periodinane-promoted oxidative dearomatization of 4,5,6,7-tetrahydroindole intermediates provides an efficient and robust access to 5,6-dihydro-1H-indol-2(4H)ones. Green, relatively mild and operationally simple characteristics of the synthetic sequence are the major advantages, which greatly amplify the developed methodology. The utility of obtained indolones as unified key precursors is demonstrated by the application of these products to the formal total syntheses of a whole pleiad of Erythrina- and Lycorine-type alkaloids, namely (±)-erysotramidine, (±)-erysotrine, (±)-erythravine, (±)-γ-lycorane, and abnormal erythrinanes (±)-coccoline and (±)-coccuvinine.
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia.
authors.forename: Ivan A
authors.identifier: 0000-0002-7195-0535
authors.initials: IA
authors.lastname: Andreev
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia.
authors.forename: Nina K
authors.identifier: 0000-0001-7602-7195
authors.initials: NK
authors.lastname: Ratmanova
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia.
authors.forename: Anton M
authors.initials: AM
authors.lastname: Novoselov
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia.
authors.forename: Dmitry S
authors.initials: DS
authors.lastname: Belov
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia.
authors.forename: Irina F
authors.initials: IF
authors.lastname: Seregina
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Leninsky Gory 1/3, 119991, Moscow, Russia. kurkin@direction.chem.msu.ru.
authors.forename: Alexander V
authors.identifier: 0000-0001-6142-9511
authors.initials: AV
authors.lastname: Kurkin
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D047151:Amaryllidaceae Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D004895:Erythrina / Q000737:chemistry*; D055772:Green Chemistry Technology / Q000379:methods; D006847:Hydrocarbons, Iodinated / Q000138:chemical synthesis / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010617:Phenanthridines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D000470:Alkaloids; D047151:Amaryllidaceae Alkaloids; D006847:Hydrocarbons, Iodinated; D007211:Indoles; D010617:Phenanthridines; C513869:1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one; C015330:lycorine
keywords: 4,5,6,7-tetrahydroindoles; alkaloids; green chemistry; thermally induced cyclization; total synthesis