Ellagitannin Chemistry. The First Total Chemical Synthesis of an Ellagitannin Natural Product, Tellimagrandin I

Feldman, Ken S.; Ensel, Susan M.; Minard, Robert D.

doi:10.1021/ja00084a015

Cited by 73 publications

(54 citation statements)

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“…In addition, an analogous reaction using substrate 8 having the same acyl groups at glucose 2,3,4,6-positions furnished 7 along with another natural gallotannin, 2,3,4,6-tetragalloyl glucose [22]. Molecular mechanics based conformational studies suggested that the precedence of the 4,6-galloyl coupling over the 2,3-or 3,4-galloyl couplings in the reaction was due to the shorter distance between the aromatic rings [20,24]. Tellimagrandin II (3), the 1-O-β-galloyl form of 7, was also synthesized using a similar methodology [23].…”

Section: Chemical Synthesis Of Ellagitannins By Biaryl Coupling Of Gamentioning

confidence: 99%

“…The first total synthesis of a natural ellagitannin was achieved by Feldman et al in a manner similar to the enzymatic HHDP formation (Scheme 17.3) [20]. A synthetic precursor 5 having two partially protected galloyl groups at glucose 4,6-positions was treated with Pb(OAc) 4 to give a cyclized product 6 and subsequent deprotection furnished tellimagrandin I (7) [21].…”

Section: Chemical Synthesis Of Ellagitannins By Biaryl Coupling Of Gamentioning

confidence: 99%

“…The (R)-DHHDP group is more common in Nature, and geraniin and related ellagitannins are widely distributed in Euphorbiaceous plants [9,10]. The stability of phyllanemblinin B (20) is apparently contradictory; however, this can be ascribed to the conformational flexibility of the molecule due to the absence of the 3,6-HHDP ester, which allows the glucopyranose to adopt a skew boat conformation and mitigate the strain of the macrocyclic ester ring [32]. Although 23 has not been found in Nature, its partial hydrolysis product, geraniinic acid A (24), was found in Geranium thunbergii together with 22 [37].…”

Section: Ellagitannins With 1 C 4 Glucopyranose Coresmentioning

confidence: 99%

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Biomimetic Synthesis and Related Reactions of Ellagitannins

Tanaka

Kouno

Nonaka³

2011

Biomimetic Organic Synthesis

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Section: Chemical Synthesis Of Ellagitannins By Biaryl Coupling Of Gamentioning

confidence: 99%

Section: Chemical Synthesis Of Ellagitannins By Biaryl Coupling Of Gamentioning

confidence: 99%

Section: Ellagitannins With 1 C 4 Glucopyranose Coresmentioning

confidence: 99%

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Biomimetic Synthesis and Related Reactions of Ellagitannins

Tanaka

Kouno

Nonaka³

2011

Biomimetic Organic Synthesis

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“…More complex ellagitannins, such as the natural compounds tellimagrandin I (162) [117], sanguiin H-5 [18], pedunculagin [118], and coriariin A (166) (Scheme 41) [119,120] have also been synthesized by the lead tetraacetate oxidative coupling procedure, with the same favorable stereoselective (S)-biaryl bond formation.…”

Section: Transfer Of Chiral Information Via the Molecular Backbonementioning

confidence: 99%

Oxidative Aryl‐Coupling Reactions in Synthesis

Lessène

Feldman

2002

Modern Arene Chemistry

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The oxidant-mediated coupling of electron-rich arene rings has served over several decades as a valuable procedure to access biaryl units. The complex mixtures of isomers that often plagued the earliest studies have gradually given way to synthetically useful product distributions upon application of more selective coupling protocols. Continual advances in the nature of the oxidant (and its attendant ligands) and more precisely defined reaction conditions have led to increasing levels of control upon CaC bond formation. Chemoselective (CaC vs. CaO bond formation with phenols; suppression of product oxidation), regioselective (o-o 0 , vs. o-p 0 vs. p-p 0 CaC bond formation), and, more recently, stereoselective (atropisomer-selective) biaryl bond formation can now be achieved in many well-defined systems. A survey of the more recent advances in these areas is presented.14.1

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“…However, very careful separation of the diastereomers by column chromatography on silica gel was still needed. Herein, we report an example of essentially complete atropdiastereoselectivity in the synthesis of diphosphine dioxide by means of intramolecular Ullmann coupling (27,34,40,41) or Fe(III)-promoted oxidative coupling (42)(43)(44)(45) with central-to-axial chirality transfer, resulting in a concomitant eight-membered ring closure. The introduction of the chiral bridge restricted the conformational rotation of the diphosphine and made it more rigid than other biaryl diphosphine ligands (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)46).…”

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confidence: 99%

Remarkably diastereoselective synthesis of a chiral biphenyl diphosphine ligand and its application in asymmetric hydrogenation

Qiu

Chan

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Essentially complete atropdiastereoselectivity was realized in the preparation of biaryl diphosphine dioxide by asymmetric intramolecular Ullmann coupling and oxidative coupling with central-toaxial chirality transfer. A bridged C2-symmetric biphenyl phosphine ligand possessing additional chiral centers on the linking unit of the biphenyl groups was synthesized. No resolution step was required for the preparation of the enantiomerically pure chiral ligand. These findings offer a general and practical tool for the development of previously uninvestigated atropdiastereomeric biaryl phosphine ligands. The diphosphine ligand was found to be highly effective in the asymmetric hydrogenation of ␣-and ␤-ketoesters, 2-(6-methoxy-2-naphthyl)propenoic acid, ␤-(acylamino)acrylates, and enol acetates.A xially chiral biaryls are not only common structural motifs in many natural products, but they are also the core of many highly effective chiral ligands for asymmetric reactions. Atropisomeric, C 2 -symmetric diphosphine ligands have played a particularly crucial role in the development of asymmetric catalysis (1-4). Therefore, it is not surprising that considerable efforts have been taken for the design and synthesis of atropisomeric ligands based on the biphenyl, binaphthyl, or other biaryl backbones (5-15). Enantiomerically pure biaryls can be obtained by aryl-aryl coupling followed by a classical resolution of the resulting atropisomers. The disadvantage of the path by resolution is that the maximum yield of the desired atropisomer is only 50% and the enantiomeric excesses (ee's) are usually Ͻ100%, not to mention that resolution procedures are frequently tedious. From a practical standpoint, it is desirable to develop efficient atroposelective methodologies for the synthesis of biaryls ligands to expand the scope of the useful catalysts. Various approaches, including desymmetrization of prochiral biaryls (16), kinetic resolution of racemic substrates (17), asymmetric catalytic coupling (18-23), and chirality transfer from central, axial, and planar asymmetry have been reported (24-38). Oxazolinemediated asymmetric Ullmann coupling was studied by Meyers and coworkers (28-30) to produce diastereomerically pure bis(oxazoline)s and corresponding enantiomerically pure biphenols and binaphthols. Previously, most of the research was focused on the syntheses of biphenols and binaphthols; in contrast, less attention was paid to the atroposelective syntheses of biaryl diphosphine oxides, the precursors of widely used diphosphine ligands. Recently, we successfully developed two diastereomeric diphosphine ligands for use in asymmetric hydrogenation reactions by stereoselective intermolecular Ullmann coupling of two chiral phosphine oxide precursors with moderate atropdiastereoselectivity (39). However, very careful separation of the diastereomers by column chromatography on silica gel was still needed. Herein, we report an example of essentially complete atropdiastereoselectivity in the synthesis of diphosphine dioxide by means of int...

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Ellagitannin Chemistry. The First Total Chemical Synthesis of an Ellagitannin Natural Product, Tellimagrandin I

Cited by 73 publications

References 0 publications

Biomimetic Synthesis and Related Reactions of Ellagitannins

Biomimetic Synthesis and Related Reactions of Ellagitannins

Oxidative Aryl‐Coupling Reactions in Synthesis

Remarkably diastereoselective synthesis of a chiral biphenyl diphosphine ligand and its application in asymmetric hydrogenation

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