Synthesis of Chiral and Modifiable Hexahydroxydiphenoyl Compounds

Asakura, Noriaki; Fujimoto, Sanji; Michihata, Naoki; Nishii, Kentaro; Imagawa, Hiroshi; Yamada, Hidetoshi

doi:10.1021/jo201750d

Cited by 37 publications

(25 citation statements)

References 47 publications

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“…The formation of the 3,4‐HHDP bridge was also possible through double esterification (Scheme ). Specifically, 12 was obtained under modified Steglich's conditions by treatment of diol 16 with ( R )‐HHDP‐dicarboxylic acid 20 , the axial chirality of which had already been determined 11. The obtained 3,4‐HHDP‐bridged compound 12 was identical to that derived through the aryl–aryl coupling described above, confirming the ( R )‐axial chirality derived in the coupling step.…”

Section: Resultssupporting

confidence: 57%

Total Synthesis of Cercidinin A

2013

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An ellagitannin, cercidinin A, was synthesized through both intramolecular coupling of gallates on a glucose moiety and double esterification of protected hexahydroxydiphenic acid to a diol. The total synthesis confirmed the revised structure of cercidinin A as 1,2,6‐tri‐O‐galloyl‐3,4‐(R)‐hexahydroxydiphenoyl (HHDP) β‐D‐glucose. This is the first synthesis of 3,4‐HHDP‐bridged ellagitannins and was achieved after overcoming two challenges: (1) full galloylation of β‐glucose hindered the formation of the 3,4‐HHDP group, and (2) the fully benzylated galloyl group, which is a routine component in ellagitannin synthesis, was not always appropriate. The solutions to these problems can be used to form a strategy for the synthesis of complex ellagitannins.

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Section: Resultssupporting

confidence: 57%

Total Synthesis of Cercidinin A

2013

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“…Thes ynthesis commenced with the preparation of allyl-and benzyl-protected (R)-HHDP diacid (R)-12 and its anhydride 13 from the known 11 (Scheme 1a). [25,31] Thus,h ydrolysis of 11 released (R)-12,w hich upon treatment with oxalyl chloride provided 13.Meanwhile, O3 of diacetone glucose (14)was acylated with 3,5-di-O-allyl-4-O-benzylgallic acid [25] to furnish 15 (Scheme 1b). After removal of the acetonide groups from 15,t he 4,6-diol of 16 was protected as p-methoxybenzylidene acetal to give 17.…”

Section: Angewandte Chemiementioning

confidence: 99%

Non‐Enzymatic Oxidation of a Pentagalloylglucose Analogue into Members of the Ellagitannin Family

et al. 2017

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The occurrence of more than 1000 structurally diverse ellagitannins has been hypothesized to begin with the oxidation of penta-O-galloyl-β-d-glucose (β-PGG) for the coupling of the galloyl groups. However, the non-enzymatic behavior of β-PGG in the oxidation is unknown. Disclosed herein is which galloyl groups tended to couple and which axial chirality was predominant in the derived hexahydroxydiphenoyl groups when an analogue of β-PGG was subjected to oxidation. The galloyl groups coupled in the following order: at the 4,6-, 1,6-, 1,2-, 2,3-, and 3,6-positions with respective S-, S-, R-, S-, and R-axial chirality. Among them, the most preferred 4,6-coupling reflected the what was observed for natural ellagitannins. A new finding was that the second best coupling occured at the 1,6-positions. With the detection of a 3,6-coupled product, this work demonstrated that even ellagitannin skeletons with an axial-rich glucose core may be generated non-enzymatically.

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“…The synthesis of the R ‐configured isomer is summarized in Scheme . The synthesis commenced with the preparation of allyl‐ and benzyl‐protected ( R )‐HHDP diacid ( R )‐ 12 and its anhydride 13 from the known 11 (Scheme a) . Thus, hydrolysis of 11 released ( R )‐ 12 , which upon treatment with oxalyl chloride provided 13 .…”

Section: Figurementioning

confidence: 99%

Non‐Enzymatic Oxidation of a Pentagalloylglucose Analogue into Members of the Ellagitannin Family

et al. 2017

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The occurrence of more than 1000 structurally diverse ellagitannins has been hypothesized to begin with the oxidation of penta-O-galloyl-b-d-glucose (b-PGG) for the coupling of the galloylg roups.H owever,t he non-enzymatic behavior of b-PGG in the oxidation is unknown. Disclosed herein is whichgalloylgroups tended to couple and whichaxial chirality was predominant in the derived hexahydroxydiphenoyl groups when an analogue of b-PGG was subjected to oxidation. The galloylg roups coupled in the following order: at the 4,6-, 1,6-, 1,2-, 2,3-, and 3,6-positions with respective S-, S-, R-, S-, and R-axial chirality.A mong them, the most preferred 4,6-coupling reflected the what was observed for natural ellagitannins.Anew finding was that the second best coupling occured at the 1,6-positions.W ith the detection of a3 ,6-coupled product, this work demonstrated that even ellagitannin skeletons with an axial-richg lucose core may be generated non-enzymatically.

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Synthesis of Chiral and Modifiable Hexahydroxydiphenoyl Compounds

Cited by 37 publications

References 47 publications

Total Synthesis of Cercidinin A

Total Synthesis of Cercidinin A

Non‐Enzymatic Oxidation of a Pentagalloylglucose Analogue into Members of the Ellagitannin Family

Non‐Enzymatic Oxidation of a Pentagalloylglucose Analogue into Members of the Ellagitannin Family

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