Total synthesis of bidensyneosides A2 and C: remarkable protecting group effects in glycosylation

Gung, Benjamin W.; Fox, Ryan M.

doi:10.1016/j.tet.2004.08.012

Cited by 19 publications

(15 citation statements)

References 20 publications

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“…Unfortunately, tetraalkyne 15 a was obtained in poor yield (< 5 %) under standard conditions. Alternatively, other well-known conditions for alkyne-alkyne coupling, such as copper-catalyzed Cadiot-Chodkiewicz coupling [17] or Negishi coupling [18] were also carried out; however, no desired product was obtained. Further hydrolysis of tetrayne 15 a was performed, but the insoluble byproduct was generated.…”

Section: Resultsmentioning

confidence: 99%

The First Total Synthesis of Cytopiloyne, an Anti‐Diabetic, Polyacetylenic Glucoside

Kumar

Tsai

Chao

et al. 2011

Chemistry A European J

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The first total synthesis of cytopiloyne 1, a novel bioactive polyacetylenic glucoside isolated from the extract of Bidens pilosa, is described. The structure of cytopiloyne was determined to be 2-β-D-glucopyranosyloxy-1-hydroxytrideca-5,7,9,11-tetrayne by using various spectroscopic methods, but the chirality of the polyyne moiety was unknown. Herein, the convergent synthesis of two diastereomers of cytopiloyne by starting from commercially available 4-(2-hydroxyethyl)-2,2-dimethyl-1,3-diozolane is described. The synthetic sequence involved two key steps: stereoselective glycosylation of the glucosyl trichloroacetimidate with 1-[(4-methoxybenzyl)oxy]hex-5-yn-2-ol to give the desired β-glycoside and the construction of the glucosyl tetrayne skeleton by using a palladium/silver-catalyzed cross-coupling reaction to form the alkyne-alkyne bond, the first such use of this reaction. Comparison between the observed and published characterization data showed the 2R isomer to be the natural product cytopiloyne.

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Section: Resultsmentioning

confidence: 99%

The First Total Synthesis of Cytopiloyne, an Anti‐Diabetic, Polyacetylenic Glucoside

Kumar

Tsai

Chao

et al. 2011

Chemistry A European J

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“…2) have been shown to inhibit histamine release in rat mast cells and the production of nitric oxide. Their interesting biological activities and chemical structures have started to attract attentions in their synthetic studies [18,19,51].…”

Section: Bidensyneosidesmentioning

confidence: 99%

“…Bidensyneoside A 1 (33) differs from its closest relative bidensyneoside A2 (34) only by the configuration of the double bond in the aglycone side chain. Since the left hand main fragment 56 was already prepared [18], to prepare (À) bidensyneoside A1 (1) and C (3), the task at hand was to prepare (E)-3-penten-1-yne and 1,3-pentadiyne, respectively. There are several reported procedures for 1,3-pentadiyne.…”

Section: Bidensyneosidesmentioning

confidence: 99%

“…Bromoalkyne 56, which was available as shown in Scheme 17 [18], along with (E)-3-penten-1-yne (59) were then subjected to the copper-catalyzed crosscoupling reaction to give the desired compound 60, the precursor to bidensyneoside A1 (33), in a remarkable 91% yield. The removal of the protecting groups of 60 was carried out by first removing the TBS groups with HF$pyridine complex in acetic acid, followed by removal of the acetate groups using a catalytic amount of K 2 CO 3 in methanol.…”

Section: Bidensyneosidesmentioning

confidence: 99%

“…Attracted by the diverse biological activities [10e15] and the challenges of introducing stereocenters into reactive compounds, we commenced our first synthesis of a naturally occurring acetylenic alcohol, (S,S)-and (R,R)-adociacetylene B (1), in 2001 [16]. After the inaugural synthesis of adociacetylene B (1), graduate student Hamilton Dickson took on the tetrayne target, minquartynoic acid [17], and Ryan Fox, an undergraduate at the time, took on the polyyne glycosides, bidensyneosides [18,19]. This account describes the syntheses of these two groups of polyyne natural products first followed by the synthesis of C 2 symmetric acetylenic compounds.…”

Section: Introductionmentioning

confidence: 99%

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Total synthesis of polyyne natural products

Gung

2008

Comptes Rendus. Chimie

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Synthese von Polyin‐Naturstoffen

Shun

Tykwinski

2006

Angewandte Chemie

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In den vergangenen fünfzig Jahren wurden Hunderte von Polyinen aus natürlichen Proben isoliert. Diese oftmals unbeständigen Verbindungen finden sich gleichsam in alltäglichen Quellen wie Gartengemüse und weniger geläufigen Quellen wie Bakterienkulturen. Die Strukturen von natürlichen Polyinen unterscheiden sich sehr stark, und entsprechend vielfältig sind die biologischen Eigenschaften dieser Naturstoffe. Frühe Syntheseansätze nutzten zum Aufbau des Polyin‐Gerüsts vorzugsweise die kupferkatalysierte oxidative Homo‐ und Heterokupplung von Alkinen. Eine Renaissance der Polyin‐Naturstoffsynthese hat in den vergangenen 25 Jahren jedoch innovative Synthesetechniken hervorgebracht: Übergangsmetallkatalysierte Alkinylierungen und asymmetrische Umwandlungen haben das Repertoire der Polyin‐Naturstoffsynthese merklich erweitert. Der Aufsatz stellt diese Verbesserungen vor und geht auf die natürliche(n) Quelle(n) und die biologische Bedeutung vieler Substanzen ein.

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Total synthesis of bidensyneosides A2 and C: remarkable protecting group effects in glycosylation

Cited by 19 publications

References 20 publications

The First Total Synthesis of Cytopiloyne, an Anti‐Diabetic, Polyacetylenic Glucoside

The First Total Synthesis of Cytopiloyne, an Anti‐Diabetic, Polyacetylenic Glucoside

Total synthesis of polyyne natural products

Synthese von Polyin‐Naturstoffen

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