Eine hoch enantioselektive Brønsted‐Säure‐katalysierte Kaskadenreaktion: organokatalytische Transferhydrierung von Chinolinen und deren Anwendung in der Synthese von Alkaloiden

Rueping, Magnus; Antonchick, Andrey P.; Theissmann, Thomas

doi:10.1002/ange.200600191

Cited by 254 publications

(45 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Rueping [83] developed an organocatalytic transfer hydrogenation cascade of 2-substituted quinolines, which was applied to the synthesis of some plant alkaloids. Through the use of 1 mol-% of binaphtholphosphate catalyst 168, [84] a stepwise hydride transfer from the Hantzsch ester (124) to quinoline 166 afforded the corresponding tetrahydroquinoline 167 in excellent yields and enantioselectivities (Scheme 42).…”

Section: Phosphatesmentioning

confidence: 99%

“…The following synthesis by Kim et al (Scheme 21) is an elegant example in which organic and transition metal catalysis complement each other. [49] The crude reaction mixture obtained from an asymmetric α-hydroxylation of butyraldehyde (83) was directly subjected to an indium-mediated allylation. Whereas the enantioselectivity was excellent (Ͼ98 % ee), the diastereoselectivity was only moderate (dr 3:2).…”

Section: α-Heterofunctionalizationsmentioning

confidence: 99%

See 1 more Smart Citation

Organocatalytic Synthesis of Drugs and Bioactive Natural Products

2007

View full text Add to dashboard Cite

show abstract

Section: Phosphatesmentioning

confidence: 99%

Section: α-Heterofunctionalizationsmentioning

confidence: 99%

Organocatalytic Synthesis of Drugs and Bioactive Natural Products

2007

View full text Add to dashboard Cite

show abstract

“…[26] Therefore, polymer network 7 was used as heterogeneous catalyst in the reduction of 2-aryl quinolones. The tetrahydroquinoline structure is a very important structural motif in many natural products and bioactive molecules, and binol-derived phosphoric acids have been used in the asymmetric transfer hydrogenation reaction of 2-aryl quinolines.…”

Section: Angewandte Chemiementioning

confidence: 99%

A Microporous Binol‐Derived Phosphoric Acid

et al. 2012

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8][9] Despite these advances, direct hydrogenation of simple pyridines is still a challenge. The inherent problems are apparent: First, substrates and corresponding products that possess strong coordination ability might cause the deactivation of catalysts.…”

mentioning

confidence: 99%

Iridium‐Catalyzed Asymmetric Hydrogenation of Pyridinium Salts

Chen

et al. 2012

Angewandte Chemie

View full text Add to dashboard Cite

As one of the most straightforward and powerful approaches for the preparation of optically active compounds, asymmetric hydrogenation has been successfully used for different types of aromatic compounds, including quinolines, isoquinolines, quinoxalines, indoles, pyrroles, furans, imidazoles, and aromatic carbocyclic ring, with excellent enantioselectivities. [1][2][3][4][5][6][7][8][9] Despite these advances, direct hydrogenation of simple pyridines is still a challenge. The inherent problems are apparent: First, substrates and corresponding products that possess strong coordination ability might cause the deactivation of catalysts. Second, pyridines have a stabilizing aromatic structure that might impede the reduction. Therefore, only limited examples of hydrogenation of specific pyridine derivatives bearing powerful electron-withdrawing substituent at the 2-or 3-position have been previously described. In 2000, Studer et al. reported the first homogeneous rhodium-catalyzed asymmetric hydrogenation of pyridines, but only poor enantioselectivity was obtained. [10] Zhang and co-workers described an efficient three-step rhodium-catalyzed asymmetric hydrogenation of nicotinates.[11] Subsequently, the group of Rueping documented the first enantioselective organocatalytic transfer hydrogenation of 3-cyano-or carbonyl-substituted pyridines using Hantzsch esters as hydrogen sources, [12] and our group also employed [{Ir(cod)Cl} 2 ]/(S)-MeO-biphep/I 2 catalyst system for asymmetric hydrogenation of specific pyridines with excellent enantioselectivities.[13] Additionally, an elegant asymmetric hydrogenation of activated pyridines, that is, N-iminopyridinium ylides, was developed by Charette et al. [14] As chiral piperidines are important building blocks for the synthesis of biologically active molecules and natural products, [15] the development of an efficient strategy for the highly challenging hydrogenation of the simple pyridines is still of great significance.Iminium salts generally exhibit higher activity than the corresponding imines in hydrogenation, [15b-l, 16] therefore we envisioned that the activation of simple pyridines as the corresponding N-benzyl-pyridinium bromides would effectively eliminate coordination ability of the substrate and thus the reactivity could be greatly enhanced. Moreover, the stoichiometric amount of hydrogen bromide generated in situ would effectively inhibit the coordination ability of the desired product through the formation of its piperidine hydrogen bromide salt (Scheme 1). Also, the benzyl protecting groups could be conveniently removed by hydrogenolysis. Herein, we disclose the iridium-catalyzed asymmetric hydrogenation of 2-substituted pyridinium salts with excellent enantioselectivity.Our investigation started with the asymmetric hydrogenation of N-benzyl-2-phenylpyridinium bromide using [{Ir(cod)Cl} 2 ]/(R)-MeO-biphep as the catalyst (Table 1). To our delight, when CH 2 Cl 2 was employed as the solvent, the reaction proceeded smoothly to give the target product in 84 % y...

show abstract

Eine hoch enantioselektive Brønsted‐Säure‐katalysierte Kaskadenreaktion: organokatalytische Transferhydrierung von Chinolinen und deren Anwendung in der Synthese von Alkaloiden

Cited by 254 publications

References 50 publications

Organocatalytic Synthesis of Drugs and Bioactive Natural Products

Organocatalytic Synthesis of Drugs and Bioactive Natural Products

A Microporous Binol‐Derived Phosphoric Acid

Iridium‐Catalyzed Asymmetric Hydrogenation of Pyridinium Salts

Contact Info

Product

Resources

About