Synthetic studies toward C-glucosidic ellagitannins: a biomimetic total synthesis of 5-O-desgalloylepipunicacortein A.
C-glucosidic ellagitannins constitute a subclass of bioactive polyphenolic natural products with strong antioxidant properties, as well as promising antitumoral and antiviral activities that are related to their capacity to interact with both functional and structural proteins. To date, most synthetic efforts toward ellagitannins have concerned glucopyranosic species. The development of a synthetic strategy to access C-glucosidic ellagitannins, whose characteristic structural feature includes an atropoisomeric hexahydroxydiphenoyl (HHDP) or a nonahydroxyterphenoyl (NHTP) unit that is linked to an open-chain glucose core by a C-aryl glucosidic bond, is described herein. The total synthesis of the biarylic HHDP-containing 5-O-desgalloylepipunicacortein A (1 β) was achieved by either using the natural ellagic acid bis-lactone as a precursor of the requested HHDP unit or by implementing an atroposelective intramolecular oxidative biarylic coupling to forge this HHDP unit. Both routes converged in the penultimate step of this synthesis to enable a biomimetic formation of the key C-aryl glucosidic bond in the title compound.
Université de Bordeaux, Institut des Sciences Moléculaires (CNRS-UMR 5255), Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac Cedex, France.
Gaëlle
G
Malik
Anna
A
Natangelo
Jaime
J
Charris
Laurent
L
Pouységu
Stefano
S
Manfredini
Dominique
D
Cavagnat
Thierry
T
Buffeteau
Denis
D
Deffieux
Stéphane
S
Quideau
D032701:Biomimetics; D005960:Glucosides / Q000138:chemical synthesis* / Q000737:chemistry*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis* / Q000737:chemistry*; D047348:Hydrolyzable Tannins / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure
C557991:5-O-desgalloylepipunicacortein A; D005960:Glucosides; D006576:Heterocyclic Compounds, 4 or More Rings; D047348:Hydrolyzable Tannins