Enantioselective electrophilic trifluoromethylation of β-keto esters with Umemoto reagents induced by chiral nonracemic guanidines

Noritake, Shun; Shibata, Norio; Nomura, Y.; Huang, Yiyong; Matsnev, Andrej V.; Nakamura, Shuichi; Toru, Takeshi; Cahard, Dominique

doi:10.1039/b909641h

Cited by 79 publications

(30 citation statements)

References 76 publications

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“…[1][2][3][4][5] Indeed, the appropriate introductiono fafluorine atom or a fluorinated group can drastically affect the biological and physical properties of am olecule andi ts physiological behavior with respect to the modeo fa ction and metabolism. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] The introduction of at rifluoromethylg roup in an enantioselective manner is one of the most challengings ynthetic problems. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] The introduction of at rifluoromethylg roup in an enantioselective manner is one of the most challengings ynthetic problems.…”

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confidence: 99%

Lanthanum‐Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent

Granados

Rivilla

Cossío

et al. 2019

Chemistry A European J

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Ah ighlye nantioselective catalytic methodf or the synthesis of quaternary a-trifluoromethyl derivatives of 3-oxo estersi sd escribed. The reaction uses lanthanum(III) triflate andc hiral PyBOX-type C 2 -symmetric ligands to generate intermediate La III complexes that incorporate an enolate moiety of the starting 3-oxo ester and the trifluoromethylation transfer reagent. The enantioselectivity of the reactions tems from the efficient blockage of one of the prochiral faces of the La III enolateb yo ne unit of the C 2 -symmetric ligand. Scheme1.Trifluoromethylation of ester 1a with La(OTf) 3 and reagents 3a,b in the presence of chiral ligands L1-3.Figure 2. Fully optimized geometries of cationic intermediates INT3 and INT4,connected by saddle point TS.Bond distances and angles are given in and degree, respectively.See Figure 1c aption for additional details. The origin of the enantioselectivef ormationo ft he C*···CF 3 bondbyb lockage of one of the prochiral faceso ft he La III -enolate of 1b is highlighted.

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confidence: 99%

Lanthanum‐Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent

Granados

Rivilla

Cossío

et al. 2019

Chemistry A European J

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“…[321] Spätere Methoden zur enantioselektiven a-Trifluormethylierung von Carbonylverbindungen nutzen die Bildung chiraler Enamine unter Organokatalyse. [321] Spätere Methoden zur enantioselektiven a-Trifluormethylierung von Carbonylverbindungen nutzen die Bildung chiraler Enamine unter Organokatalyse.…”

Section: Fluorierungenunclassified

Einführung von Fluor und fluorhaltigen funktionellen Gruppen

2013

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Die wichtigsten konzeptionellen Fortschritt auf dem Gebiet der Fluorierungen der letzten zehn Jahre wurden durch die Organo‐ und Übergangsmetallkatalyse ermöglicht. Die schwierigste Umwandlung ist weiterhin die Bildung der C‐F‐Stammbindung, was in erster Linie eine Folge der hohen Hydratationsenergie von Fluorid, starker Metall‐Fluor‐Bindungen und der hoch polarisierten Bindungen zu Fluor ist. Den meisten Fluorierungen fehlt es immer noch an Allgemeingültigkeit, Vorhersagbarkeit und Kosteneffizienz. Trotz der Einschränkungen sind fluorierte Verbindungen mit modernen Fluorierungsmethoden leichter zugänglich als je zuvor. Vor allem beginnen sich die modernen Methoden auf Forschungsgebiete auszuwirken, die keine großen Materialmengen benötigen, z. B. die Wirkstoffentwicklung und die Positronenemissionstomographie. Diese Entwicklungen werden in diesem Aufsatz zusammengefasst und vor dem Hintergrund konventioneller Fluorierungsmethoden diskutiert.

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“…The best enantiomeric excess was 45% for 20% yield [17]. In 2008–2009, we found that chiral nonracemic cinchona alkaloids and guanidines act as Brønsted bases to generate ammonium or guanidinium enolates for the enantioselective electrophilic trifluoromethylation of β-keto esters with Umemoto reagents with good enantioselectivities in the range 60–71% (Scheme 9) [18–19]. …”

Section: Reviewmentioning

confidence: 99%

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

Shibata¹,

Matsnev²,

Cahard³

2010

Beilstein J. Org. Chem.

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245

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SummarySince the discovery by Yagupolskii and co-workers that S-trifluoromethyl diarylsulfonium salts are effective for the trifluoromethylation of thiophenolates, the design and synthesis of electrophilic trifluoromethylating reagents have been extensively researched in both academia and industry, due to the significant unique features that trifluoromethylated compounds have in pharmaceuticals, agricultural chemicals, and functional materials. Several effective reagents have been developed by the groups of Yagupolskii, Umemoto, Shreeve, Adachi, Magnier, Togni and Shibata. Due to the high stability and reactivity of these reagents, a series of Umemoto reagents, Togni reagent and Shibata reagent are now commercially available. In this review, we wish to briefly provide a historical perspective of the development of so-called “shelf-stable electrophilic trifluoromethylating reagents”, although this field is in constant development.

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Enantioselective electrophilic trifluoromethylation of β-keto esters with Umemoto reagents induced by chiral nonracemic guanidines

Cited by 79 publications

References 76 publications

Lanthanum‐Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent

Lanthanum‐Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent

Einführung von Fluor und fluorhaltigen funktionellen Gruppen

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

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