Catalytic asymmetric hetero-Diels–Alder route to a key intermediate for the synthesis of calyxin L

Washio, Takuya; Nambu, Hisanori; Anada, Masahiro; Hashimoto, Shunichi

doi:10.1016/j.tetasy.2007.10.025

Cited by 21 publications

(5 citation statements)

References 22 publications

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“…1–4 In particular, multicomponent reactions provide valuable functionalized heterocyclic compounds containing a 4-aryltetrahydropyran moiety, 5–7 which is the core unit of many biologically active compounds including epicalyxin F and calyxins I and L with antiproliferative activity against human fibrosarcoma HT-1080, and murine colon 26-L5 carcinoma cells. 8–11 A one-pot acid-catalyzed Prins–Friedel–Crafts reaction between a carbonyl compound, a homoallylic alcohol and an aromatic hydrocarbon is an efficient method for the synthesis of heterocycles with the 4-aryltetrahydropyran moiety. 12–15 This reaction involves Prins cyclization via interaction of a carbonyl compound and a homoallylic alcohol with the formation of an oxocarbenium ion that undergoes an intramolecular π-bond attack to construct a new carbon–carbon bond with a subsequent Friedel–Crafts alkylation with an arene nucleophile.…”

Section: Introductionmentioning

confidence: 99%

MWW-type zeolite nanostructures for a one-pot three-component Prins–Friedel–Crafts reaction

Barakov

Shcherban

Petrov

et al. 2022

Inorg. Chem. Front.

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Section: Introductionmentioning

confidence: 99%

MWW-type zeolite nanostructures for a one-pot three-component Prins–Friedel–Crafts reaction

Barakov

Shcherban

Petrov

et al. 2022

Inorg. Chem. Front.

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“…More than 50 polyphenolic constituents of the seeds of Alpinia blepharocalyx have been isolated by Kadota and co-workers, and several of them have been shown to possess significant antiproliferative activity against colon 26-L5 carcinoma and HT-1080 fibrosarcoma cells. Not surprisingly, these compounds have attracted the attention of several groups, resulting in both partial and total syntheses of a number of analogues. Calyxin I ( 1 ) along with the epimeric analogues calyxin J ( 2 ) and epicalyxin J ( 3 ) comprise a subset of isolates that are characterized by the presence of a novel bis- C -arylpyranoside moiety embedded in a tetrahydropyranochromene framework.…”

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confidence: 99%

Evidence for π-Stacking as a Source of Stereocontrol in the Synthesis of the Core Pyranochromene Ring System common to Calyxin I, Calyxin J, and Epicalyxin J

et al. 2009

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A diastereoselective synthesis of the tetrahydropyranochromene ring system common to several natural product isolates of Alpinia blepharocalyx is reported. We have shown that a stereochemical preference exists for a syn configuration between the anomeric aryl substituents, representative of the C-7 and C-7′ substituents in the natural products. Further, our results show that stereocontrol is under kinetic control, and calculations suggest that a favorable π-stacking interaction may be the source of this stereocontrol.More than fifty polyphenolic constituents of the seeds of Alpinia blepharocalyx have been isolated by Kadota and coworkers, 1 and several of them have been shown to possess significant antiproliferative activity against colon 26-L5 carcinoma and HT-1080 fibrosarcoma cells. Not surprisingly, these compounds have attracted the attention of several groups, resulting in both partial 2 and total 3 syntheses of a number of analogues. Calyxin I (1) along with the epimeric analogues calyxin J (2) and epicalyxin J (3) comprise a subset of isolates that are characterized by the presence of a novel bis-C-arylpyranoside moiety embedded in a tetrahydropyranochromene framework. To date, synthetic work in this area has been sparse. Li and coworkers have reported stereoselective syntheses of compounds 4 and 5 using the Prins cyclization, 4 but they did not report the formation of bis-aryl derivatives by their route. We therefore chose compound 6 as a model synthetic target to see if a stereochemical preference exists for the aryl substituents to be syn to each other as indicated, analogous to the C-7 and C-7′ positions in the natural products. The nature of the interaction between the two aromatic rings at these positions would be important, and the possibility of a favorable π-stacking effect was not ruled out as a controlling factor. 5 kmead@ra.msstate.edu. Supporting Information Available: 1 H and 13 C spectra for new compounds, and details of the computational studies. This material is available free of charge via the Internet at http://pubs.acs.org. Our route began with the racemic lactone 8, which was prepared in 56% yield by a palladiumcatalyzed addition of 2-benzyloxy-iodobenzene 7 6 to 5,6-dihydro-2H-pyran-2-one (Scheme 1). A directed aldol reaction of lactone 8 with p-methoxybenzaldehyde, via its boron enolate, then gave alcohol 9 in a 91% yield as a single isomer, 7 which was cleanly converted to the diol 10 in 94% yield under standard hydrogenation conditions. Exposure of diol 10 to Lewis acid then provided compound 11 diastereomerically pure (79% from compound 9). The stereochemistry of compound 11 was easily assignable based on proton NMR coupling constants. A doublet at δ5.22 (J = 10 Hz) established the trans-diaxial relationship between H a and H b , while a doublet of doublets at δ3.08 (J = 10, 13 Hz) confirmed the same relationship between H a and H c . Although the formation of 11 from diol 10 proceeded with complete inversion of configuration, establishment of the newly-formed ring stere...

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“…The oxa-Diels–Alder (ODA) reaction between aldehydes and 1,3-dienes is arguably the most efficient and atom economical approach for the construction of six-membered dihydropyran scaffolds in a concerted step. This tactic of cycloaddition of aldehydes to diene has been widely exploited in the syntheses of natural products and physiologically active substances. − Erstwhile reports of such crucial ODA reactions have been restricted to the reaction of electron-rich Danishefsky’s, Brassard’s, or Rawal’s diene with a broad range of aldehydes or the reaction of activated aldehydes containing electron-withdrawing groups (e.g., glyoxylates) with an array of dienes, thus narrowing down the possibility for the simple dienes. , The reaction between aldehydes and simple dienes is mostly dictated by the interaction between the highest occupied molecular orbital (HOMO) of the diene and the lowest unoccupied molecular orbital (LUMO) of the dienophile, i.e., aldehydes. , As compared to the activated aldehydes, unactivated aldehydes have a higher LUMO level of the π C–O bond. In contrast to the electron-rich dienes, the simple dienes have a lower level of HOMO.…”

Section: Introductionmentioning

confidence: 99%

Cooperativity in Diiron(III)porphyrin Dication Diradical-Catalyzed Oxa-Diels–Alder Reactions: Spectroscopic and Mechanistic Insights

Sarkar

Samanta

et al. 2022

ACS Catal.

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Here, we delineate a maiden example of a diiron(III) dication diradical porphyrin dimer as a competent catalyst for the oxa-Diels–Alder type reaction of aldehydes with 1,3-dienes, which is a cardinal reaction in the syntheses of natural products. This catalyzed process does not demand the use of electron-deficient aldehydes such as glyoxylic acid derivatives or activated electron-rich 1,3-dienes such as Danishefsky’s, Brassard’s, or Rawal’s diene. The robust catalyst exhibited high functional group tolerance. The computational studies corroborated the detailed spectroscopic investigation, which focused on the pivotal roles played by the metal ion as the Lewis acidic center in combination with counteranions and also enabled us to delve deeper into the reaction mechanism. Previously developed methodologies invariably require dissociation of the iron-axial bond of the catalyst; on the contrary, the axial ligand of the catalyst remains intact during the catalysis reported here. The use of a dication diradical iron(III)porphyrin as the Lewis acid catalyst facilitates activation of the aldehyde via coordination whose formation has also been confirmed experimentally. Moreover, the counteranion has a considerable effect on the reaction pathway; its coordination to the metal inhibits the coordination of the substrate to form the product. The efficacy of employing such a diheme catalyst over a monoheme analogue is manifested in the cooperative effect, which resulted in a lower catalyst loading with excellent yields.

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Catalytic asymmetric hetero-Diels–Alder route to a key intermediate for the synthesis of calyxin L

Cited by 21 publications

References 22 publications

MWW-type zeolite nanostructures for a one-pot three-component Prins–Friedel–Crafts reaction

MWW-type zeolite nanostructures for a one-pot three-component Prins–Friedel–Crafts reaction

Evidence for π-Stacking as a Source of Stereocontrol in the Synthesis of the Core Pyranochromene Ring System common to Calyxin I, Calyxin J, and Epicalyxin J

Cooperativity in Diiron(III)porphyrin Dication Diradical-Catalyzed Oxa-Diels–Alder Reactions: Spectroscopic and Mechanistic Insights

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