Acid-catalyzed Epimerization of Kobophenol A to Carasinol B

Cheng, Kejun; Liang, Gaolin; Hu, Chun

doi:10.3390/molecules13040938

Cited by 5 publications

(2 citation statements)

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“…The final step toward total synthesis of eleuthoide A (1) For further enhancement of the yield, we expected that epimerization 23 may play a role in converting one isomer into another. As a result, epimerization was attempted under several conditions as illustrated in Scheme 7.…”

Section: Methodsmentioning

confidence: 99%

Total Synthesis of Eleuthoside A; Application of Rh-Catalyzed Intramolecular Cyclization of Diazonaphthoquinone

Othman

Otsuka

Takahashi

et al. 2017

Synlett

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The first total synthesis of (±)-eleutherol and eleuthoside A, the natural cytotoxic substances extracted from medicinal Indonesian plant, is described. First, the synthesis of (±)-eleutherol has been accomplished in nine steps starting from bromo methoxy aldehyde with the aid of diazo-transfer chemistry approach. Second, a metal-catalyzed intramolecular cyclization reaction of the corresponding diazonaphthoquinone led to the desired eleuotherol, which served as a precursor to eleuthoside A. Then, several glycosidation routes, using different glucosyl donors, were experimented to reach effective O-glycosidation of eleutherol. The only successful strategy involved Koenigs–Knorr glycosidation using peracetyl glycosyl bromide in the presence of Ag2O and quinoline. This strategy furnished our desired acetylated glycoside of β-configuration, regioselectively. Finally, deacetylation and successive separation of diastereomers were conducted to give eleuthoside A.

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Section: Methodsmentioning

confidence: 99%

Total Synthesis of Eleuthoside A; Application of Rh-Catalyzed Intramolecular Cyclization of Diazonaphthoquinone

Othman

Otsuka

Takahashi

et al. 2017

Synlett

View full text Add to dashboard Cite

show abstract

“…An illustration published recently for a p-hydroxybenzyl-substituted furanic ring in the stilbene tetramer kobophenol A (Caragana sinica, Fabaceae) challenges the conservation of medicinal extracts [83]. Similarly, radix of Asarum heterotropoides (Aristolochiaceae), a Chinese medicinal plant, contains furofuranic lignans, among which sesamin (198) and asarinin (199) are identified as main active principles.…”

Section: Epimerizationmentioning

confidence: 99%