Studies on the synthesis of mavacurine-type indole alkaloids. First total synthesis of (±)-2,7-dihydropleiocarpamine

Bennasar, M.‐Lluïsa; Zulaica, Ester; Jiménez, Juan M.; Bosch, Joan

doi:10.1021/jo00079a021

Cited by 40 publications

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“…Akuammilans, [8] strychnans, [9] and mavacurans [10] have been the subject of very intense synthetic efforts but, al atestage bioinspired oxidative cyclization of ag eissoschizinetype structure was performed only on afew occasions. [11][12][13] In aseminal study,Martin et al reported the direct cyclization of 16-deformyl-geissoschizinel eading directly to akuammicine (9).…”

Section: Geissochizine(1)isconsideredtobeacommonbiosyntheticmentioning

confidence: 99%

Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for Enantioselective Total Synthesis of Mavacuran Alkaloids

et al. 2019

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Reported is the enantioselective total syntheses of mavacuran alkaloids,( + +)-taberdivarine H, (+ +)-16-hydroxymethyl-pleiocarpamine,a nd (+ +)-16-epi-pleiocarpamine,a nd their postulated biosynthetic precursor 16-formyl-pleiocarpamine.This family of monoterpene indole alkaloids is atarget of choice since some of its members are subunits of intricate bisindole alkaloids such as bipleiophylline.I nspired by the biosynthetic hypothesis,a no xidative coupling approach from the geissoschizine framework to form the N1ÀC16 bond was explored. Quaternization of the aliphatic nitrogen center was key to achieving the oxidative coupling induced by KHMDS/I 2 as it masks the nucleophilicity of the aliphatic nitrogen center and locksi nt he required cis conformation.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.Zuschriften Scheme 3. Synthesis of (+ +)-16-deformyl-geissoschizine [(+ +)-22], (+ +)-geissoschizine [(+ +)-1], and the geissoschizine malonate (À)-23 according to our previous work. [13] AIBN = 2,2'-azobisisobutyronitrile, Boc = tert-butoxycarbonyl, COD = 1,5-cyclooctadiene, DMAP = 4-(N,Ndimethylamino)pyridine, LDA = lithium diisopropylamide, TFA = trifluoroacetica cid.Scheme 4. Total synthesis of (+ +)-16-epi-pleiocarpamine [(+ +)-5]a nd (+ +)-16-hydroxymethyl pleiocarpamine[(+ +)-3]byN 1 ÀC16 oxidative cyclization from N4-PMB-geissoschizinium derivatives. DIBAL-H = diisobutylaluminum hydride, DMF = N,N-dimethylformamide, PMB = pmethoxybenzyl, TMS = trimethylsilyl.

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Section: Geissochizine(1)isconsideredtobeacommonbiosyntheticmentioning

confidence: 99%

Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for Enantioselective Total Synthesis of Mavacuran Alkaloids

et al. 2019

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“…[8][9][10] Bei der Konstruktion des pentacyclischen Ringsystems von Apogeissoschizin (17) wurden drei verschiedene Routen versucht, um die Zwei-Kohlenstoffatom-Brücke an der Indol-3-Position einzuführen. [8] Die erste beinhaltete eine elektrophile Cyclisierung des Dithioacetals 10, die aber nur zu 11 in 9 % Ausbeute über zwei Stufen führte (Schema 3).…”

Section: Photocyclisierung Von 2-substituierten Indolenunclassified

“…[9] Die Synthese sieht den Gerüstaufbau dergestalt vor, dass der Ringschluss über die Witkop-Cyclisierung an der Indol-3-Position auf einer späten Stufe erfolgen soll. Bosch [11] Reduktion der Doppelbindung zum Ethylrest und nachfolgende Bestrahlung führten zu Ausbeuten um 20 % für das cyclisierte Produkt.…”

Section: Photocyclisierung Von 2-substituierten Indolenunclassified

Die Witkop‐Cyclisierung: eine photoinduzierte C‐H‐Aktivierung des Indolsystems

et al. 2013

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Untersuchungen von photochemisch induzierten Redoxprozessen leisten einen besonderen Beitrag zur organischen Photochemie und zu ihrer Anwendungen in der Synthese komplexer Zielstrukturen. Die richtige Wahl des Reduktions‐ und Oxidationspotentiale sowie die Energie des angeregten Zustands von Akzeptor und Donor müssen richtig gewählt werden, damit in diesem Redoxprozess über einen Einelektronentransfer ein intermediäres Radikalion erzeugt werden kann, das schließlich zu den Produkten weiterreagiert. Die Witkop‐Cyclisierung stellt eine intramolekulare Variante eines solchen Prozesses dar – typischerweise mit einem Indol‐Heterocyclus als Elektronendonor. Der synthetische Mehrwert dieser Reaktion besteht in einer C‐C‐Bindungsknüpfung ohne die sonst notwendige Präfunktionalisierung des Indolkerns. Dieser Kurzaufsatz behandelt bereits erfolgte Anwendungen der Reaktion und möchte zu ihrer Weiterentwicklung vor allem an komplexen Systemen anstoßen.

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“…The aziridinyl propargylic ester substrates (Table 3) were prepared by acylation of the corresponding aziridine propargylic alcohols 48, which were synthesized from aziridinyl aldehyde 47 via a highly diastereoselective (dr > 95%) 1,2-addition of the corresponding alkyllithium or Grignard reagent. The aziridinyl propargylic esters 49a-i on cycloisomerisation using Pt(II) catalysis (10 mol% of PtCl 2 , 0.2 M in toluene, 100 C, 3 h) afforded the corresponding 1,2-DHP products 50a-i in moderate to good yields (Table 3).…”

mentioning

confidence: 99%

“…The rst total synthesis of (AE)-2,7-dihydropleiocarpamine 295 has been reported by Bennasar, et al 100 via the synthesis of 1,4-dihydropyridine 291 as an intermediate (Scheme 86). The 1,4-dihydropyridine 291 was synthesized from nucleophilic addition of 263 on pyridinium salt 290 in the presence of LDA in THF.…”

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confidence: 99%

Synthesis, utility and medicinal importance of 1,2- & 1,4-dihydropyridines

2017

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Dihydropyridine (DHP) is among the most beneficial scaffolds that have revolutionised pharmaceutical research with unprecedented biological properties. Over the years, metamorphosis of easily accessible 1,2-and 1,4-dihydropyridine (1,4-DHP) intermediates by synthetic chemists has generated several drug molecules and natural products such as alkaloids. The 1,4-dihydropyridine (1,4-DHP) moiety itself is the main fulcrum of several approved drugs. The present review aims to collate the literature of 1,2-and the 1,4-DHPs relevant to synthetic and medicinal chemists. We will describe various methodologies that have been used for the synthesis of this class of compounds, including the strategies which can furnish enantiopure DHPs, either by asymmetric synthesis or by chiral resolution.We will also elaborate the significance of DHPs towards the synthesis of natural products of medicinal merit.

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Studies on the synthesis of mavacurine-type indole alkaloids. First total synthesis of (±)-2,7-dihydropleiocarpamine

Cited by 40 publications

References 0 publications

Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for Enantioselective Total Synthesis of Mavacuran Alkaloids

Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for Enantioselective Total Synthesis of Mavacuran Alkaloids

Die Witkop‐Cyclisierung: eine photoinduzierte C‐H‐Aktivierung des Indolsystems

Synthesis, utility and medicinal importance of 1,2- & 1,4-dihydropyridines

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