Semipinacol Rearrangement in Natural Product Synthesis

Song, Zhenlei; Fan, Chun-An; Tu, Yong‐Qiang

doi:10.1021/cr200055g

Cited by 449 publications

(219 citation statements)

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“…The influence of position and electronic nature of substituents on the phenyl group was investigated. Almost all substrates with a substituent on the meta-or para-position of the phenyl group provided the bketoesters in excellent enantioselectivities (91-96 % ee) and good yields (80-96 %; entries [4][5][6][7][8][9][10][11][12]. Particularly, a 96 % yield was obtained when 4-MeOC 6 H 4 -substituted benzoyl group was employed, owing to the excellent regioselectivity of the transformation.…”

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confidence: 99%

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Tan

Hao

et al. 2014

Angew Chem Int Ed

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A catalytic asymmetric intramolecular homologation of simple ketones with α-diazoesters was firstly accomplished with a chiral N,N'-dioxide-Sc(OTf)3 complex. This method provides an efficient access to chiral cyclic α-aryl/alkyl β-ketoesters containing an all-carbon quaternary stereocenter. Under mild conditions, a variety of aryl- and alkyl-substituted ketone groups reacted with α-diazoester groups smoothly through an intramolecular addition/rearrangement process, producing the β-ketoesters in high yield and enantiomeric excess.

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confidence: 99%

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Tan

Hao

et al. 2014

Angew Chem Int Ed

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“…[9] Im ersten Schritt wird die Doppelbindung zwischen C-2 und C-3 des Chinolingerüsts mit AuaG epoxidiert. Anschließend wird die N-Hydroxygruppe deprotoniert, und die Carbonylgruppe wird durch koordinative Protonierung aktiviert.…”

Section: Abbildung 2 Lc-ms-analyse Der Umsetzung Von Aurachin C (1) unclassified

“…[7,8] PinakolUmlagerungen wurden für die Biosynthese von verschiedenen Sekundärmetaboliten wie Aflatoxin B1, (+)-Liphagal, (+)-Asteltoxin, Brevianamid, Paraherquamid B, Versicolamid B und Notoamid vorgeschlagen. [9][10][11] Allerdings konnte bis jetzt keiner dieser hypothetischen Biosynthesewege biochemisch nachgewiesen werden, wenngleich die vorgeschlagenen Mechanismen als biomimetische Ansätze für die Totalsynthese der Naturstoffe genutzt wurden. [9] Bis heute konnte kein enzymatisches System nachgewiesen werden, das für die Pinakol-Umlagerung während der Biosynthese von Sekundärmetaboliten zuständig ist.…”

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“…[9][10][11] Allerdings konnte bis jetzt keiner dieser hypothetischen Biosynthesewege biochemisch nachgewiesen werden, wenngleich die vorgeschlagenen Mechanismen als biomimetische Ansätze für die Totalsynthese der Naturstoffe genutzt wurden. [9] Bis heute konnte kein enzymatisches System nachgewiesen werden, das für die Pinakol-Umlagerung während der Biosynthese von Sekundärmetaboliten zuständig ist. Für den Primärmetabo-lismus wurden lediglich zwei Beispiele bei der Biosynthese von verzweigten Aminosäuren und von 1-Desoxy-d-xylulose-5-phosphat beschrieben.…”

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Eine Semipinakol‐Umlagerung – katalysiert durch ein Enzymsystem mit difunktioneller FAD‐abhängiger Monooxygenase

et al. 2012

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“…The vicinal diols of ponasterone A and ponasteroside A would be feasible to facilitate pinacol rearrangement in such environment. 17 The mild enzymatic deglycosylation of ponasteroside A would be a potent competitor for the preparation of ponasterone A.…”

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Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GT_BP1with in situ product removal

Fan

et al. 2017

RSC Adv.

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A glycosyltransferase GT BP1 from Bacillus pumilus BF1 was isolated. Efficient production of ponasterone A was achieved by the recombinant E. coli/gt BP1 in a biphasic system with a molar yield of 92.7%. This in situ product removal provided the "driving force" for shifting the reaction equilibrium towards the synthesis of the product.Ponasterone A, an insect-molting steroid hormone, was rst isolated from the herb Podocarpus nakii HAY, a remedy for cancer.1 This compound was found to be an efficient inducer and to allow precise control of gene expression at specic times and with high tissue specicity.2,3 Ponasterone A-inducible wildtype p53 protein-expressing clones have been established for potential applications in cancer therapy.4 Recently, ponasterone A was found to be widely distributed in ferns 5 such as Brainea insignis 6 and Pteridiumaquilinum var. Latiusculum. 7 However, the very low content (about 0.0096 mg g À1 in the rhizomes of Brainea insignis) 6 and complex molecular structure of this effective component contained in medicinal plants have made its purication and synthesis particularly challenging. The chemical synthesis of ponasterone A from 20-hydroxyecdysone with multiple complicated reactions was investigated, with total yields of only 2.1%. 8Ponasteroside A (ponasterone A 3-b-D-glucopyranoside) is the glycoside of ponasterone A, 9 which is abundant in Brainea insignis.6 Otaka reported that the stimulatory effects of ponasteroside A on protein expression in mice were lower than those of ponasterone A.10 A biocatalytic approach was shown to be an efficient strategy for steroid preparation from the steroidal glycoside owing to its high selectivity, mild reaction conditions, and environmental compatibility. Diosgenin could be produced through biotransformation of Dioscorea zingiberensis 11 or through biotransformation of zingiberen newsaponin.12 Additionally, dioscin could be prepared through biotransformation of steroidal saponins, and progenin III (prosapogenin A of dioscin) could be prepared through biotransformation of dioscin.13 To the best of our knowledge, there are no reports on the enzymatic preparation of ponasterone A.In this study, we reported the enzymatic preparation of ponasterone A from ponasteroside A for the rst time. Bacillus pumilus BF1, a newly isolated bacterium, showed high activity in converting ponasteroside A to ponasterone A. The glycosyltransferase GT BP1 was cloned and expressed efficiently in E. coli BL21. With the strategy of in situ product removal (ISPR), efficient synthesis of ponasterone A catalyzed by recombinant E. coli/gt BP1 was successfully achieved. The successive production of ponasterone A was also discussed.Ponasteroside A was reported to be abundant in the rhizomes of Brainea insignis 6 and used as the main carbon source in screening medium. To obtain the target microbes, soil samples were collected from Brainea insignis gardens. Approximately 36 strains with the ability to biotransform ponasteroside A were screened from 200 samples. The strain BF1...

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Semipinacol Rearrangement in Natural Product Synthesis

Cited by 449 publications

References 298 publications

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Eine Semipinakol‐Umlagerung – katalysiert durch ein Enzymsystem mit difunktioneller FAD‐abhängiger Monooxygenase

Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GT_BP1with in situ product removal

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Semipinacol Rearrangement in Natural Product Synthesis

Cited by 449 publications

References 298 publications

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Catalytic Asymmetric Intramolecular Homologation of Ketones with α‐Diazoesters: Synthesis of Cyclic α‐Aryl/Alkyl β‐Ketoesters

Eine Semipinakol‐Umlagerung – katalysiert durch ein Enzymsystem mit difunktioneller FAD‐abhängiger Monooxygenase

Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GTBP1with in situ product removal

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Product

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Efficient synthesis of ponasterone A by recombinant Escherichia coli harboring the glycosyltransferase GT_BP1with in situ product removal