Total Synthesis of Palodesangren B Trimethyl Ether and D Dimethyl Ether via a Late-Stage Formation of 2<i>H</i>-Pyran-2-one of the Tetrahydrobenzo[<i>c</i>]pyranochromenone Core

Tangdenpaisal, Kassrin; Songthammawat, Poramate; Akkarasereenon, Kornkamon; Chuayboonsong, Kanokpish; Ruchirawat, Somsak; Ploypradith, Poonsakdi

doi:10.1021/acs.joc.9b01596

Cited by 7 publications

(12 citation statements)

References 72 publications

(38 reference statements)

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“…We next attempted to install the final ring A through our previously developed reaction sequence toward palodesangren derivatives, comprising the Casnati–Skattebøl ortho -formylation, Wittig methylenation, acryloylation, and Ru(II)-catalyzed ring-closing metathesis as shown in Scheme . Thus, with the tricyclic alcohol 37 in hand, we next performed the MgCl 2 -mediated Casnati–Skattebøl ortho -formylation of 37 ; however, such reaction proved to be futile under different conditions. This disappointing ortho -formylation prompted us to consider an alternative vinylation without the intermediacy of the corresponding aldehyde.…”

Section: Resultsmentioning

confidence: 94%

“…As a model, we first employed the diene 34 and a simplified chalcone 35 for the synthesis of the common tetracyclic core 6 (Scheme ). The Diels–Alder reaction between the diene 34 and the chalcone 35 afforded the adduct 36 in 74% yield as a 1:0.6 mixture of the endo:exo isomers.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, we considered utilizing a two-step process of iodination/vinylation of 37 via Suzuki cross-coupling. From our previous work, we found that the Casnati–Skattebøl ortho -formylation preferably occurred at C2 of the tricyclic alcohol structurally similar to 37 . This result would entail the regioselective iododination at the very same position to provide the tricyclic iodophenol 38 , which, in turn, could be converted into the prerequisite vinyl moiety.…”

Section: Resultsmentioning

confidence: 99%

“…Because of the structural uniqueness of palodesangrens, our research group has developed a biosynthesis-inspired strategy for the synthesis of the tricyclic cores 10 as well as palodesangren B trimethyl ether and palodesangren D dimethyl ether 11 (Scheme 2). Using thermal intermolecular Diels−Alder reactions between the electron-rich dienes 22 and the electron-poor chalcones bearing acetates (23a or 23b) furnished the methylcyclohexene ring 24.…”

Section: ■ Introductionmentioning

confidence: 99%

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Total Synthesis of Palodesangrens A and C

et al. 2021

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Palodesangrens A and C along with the common tetracyclic core are prepared from simple benzaldehyde and acetophenone derivatives in a 10-step longest linear sequence which featured the Diels–Alder reaction forming the cyclohexene moiety, LiAlH4 isomerization, stereoselective acid-catalyzed cyclization forming the chroman moiety, regioselective iodination/vinyl Suzuki cross-coupling reaction, and ring-closing metathesis (RCM) forming the 2H-pyran-2-one. Overall, the desired palodesangrens A and C are obtained in 6.1% and 6.4% yields, respectively.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Total Synthesis of Palodesangrens A and C

et al. 2021

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“…Compounds 8 and 9 were obtained as a pale yellow amorphous powder and a yellow amorphous powder, respectively. Their structures were elucidated as ( E )-1-(3,4-dihydroxyphenyl)-3-(4-hydroxy-2-methoxyphenyl)-prop-2-en-1-one ( 8 ) and loureirin C ( 9 ) by comparing their 1 H-NMR data ( Figures S26 and S27 ) with those in the literatures [ 17 , 18 ].…”

Section: Resultsmentioning

confidence: 99%

Biotransformation of the Phenolic Constituents from Licorice and Cytotoxicity Evaluation of Their Metabolites

Xiao

Han

Lee

2021

IJMS

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Biotransformation of four bioactive phenolic constituents from licorice, namely licoisoflavanone (1), glycyrrhisoflavone (2), echinatin (3), and isobavachalcone (4), was performed by the selected fungal strain Aspergillus niger KCCM 60332, leading to the isolation of seventeen metabolites (5–21). Structures of the isolated compounds were determined on the basis of extensive spectroscopic methods, twelve of which (5–7, 10–17 and 19) have been previously undescribed. A series of reactions including hydroxylation, hydrogenation, epoxidation, hydrolysis, reduction, cyclization, and alkylation was observed in the biotransformation process. All compounds were tested for their cytotoxic activities against three different human cancer cell lines including A375P, MCF-7, and HT-29. Compounds 1 and 12 exhibited most considerable cytotoxic activities against all the cell lines investigated, while compounds 2 and 4 were moderately cytotoxic. These findings will contribute to expanding the chemical diversity of phenolic compounds, and compounds 1 and 12 may serve as leads for the development of potential cancer chemopreventive agents.

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Mulberry Diels–Alder-type adducts: isolation, structure, bioactivity, and synthesis

Luo

Zhu

Zou

et al. 2022

Nat. Prod. Bioprospect.

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Mulberry Diels–Alder-type adducts (MDAAs) are unique phenolic natural products biosynthetically derived from the intermolecular [4 + 2]-cycloaddition of dienophiles (mainly chalcones) and dehydroprenylphenol dienes, which are exclusively distributed in moraceous plants. A total of 166 MDAAs with diverse skeletons have been isolated and identified since 1980. Structurally, the classic MDAAs characterized by the chalcone-skeleton dienophiles can be divided into eight groups (Types A − H), while others with non-chalcone dienophiles or some variations of classic MDAAs are non-classic MDAAs (Type I). These compounds have attracted significant attention of natural products and synthetic chemists due to their complex architectures, remarkable biological activities, and synthetic challenges. The present review provides a comprehensive summary of the structural properties, bioactivities, and syntheses of MDAAs. Cited references were collected between 1980 and 2021 from the SciFinder, Web of Science, and China National Knowledge Internet (CNKI). Graphical Abstract

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Total Synthesis of Palodesangren B Trimethyl Ether and D Dimethyl Ether via a Late-Stage Formation of 2H-Pyran-2-one of the Tetrahydrobenzo[c]pyranochromenone Core

Cited by 7 publications

References 72 publications

Total Synthesis of Palodesangrens A and C

Total Synthesis of Palodesangrens A and C

Biotransformation of the Phenolic Constituents from Licorice and Cytotoxicity Evaluation of Their Metabolites

Mulberry Diels–Alder-type adducts: isolation, structure, bioactivity, and synthesis

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