Stereoselective syntheses of heterocycles with lithiated methoxyallene

Reißig, Hans‐Ulrich; Hormuth, Stephan; Schade, Wolfgang; Amombo, Marlyse Okala; Watanabe, Tetsu; Pulz, Robert; Hausherr, Arndt; Zimmer, Reinhold

doi:10.1002/jhet.5570370316

Cited by 28 publications

(6 citation statements)

References 40 publications

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“…All the examples collected here show the potential of this approach to highly functionalized heterocycles, furnishing compounds with a very high degree of structural diversity that should be of interest in drug synthesis or material science. The versatility of alkoxyallenes [11–20 65–66] as easily available C 3 building blocks is key for this prosperousness.…”

Section: Resultsmentioning

confidence: 99%

“…Not surprisingly, simple or functionalized allenes have also been used in multicomponent processes and – dependent on the substitution pattern of the allene – a remarkable variety of reactions and product types are known using the three-carbon backbone of these reactive compounds [10]. During the exploration of alkoxyallene chemistry [11–20] we accidently discovered a new three-component reaction leading to β-ketoenamides that are uniquely functionalized alkenes and suitable for a variety of subsequent reactions, in particular in heterocyclic synthesis.…”

Section: Introductionmentioning

confidence: 99%

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The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

Lechel

Kumar

Bera

et al. 2019

Beilstein J. Org. Chem.

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The LANCA three-component reaction of lithiated alkoxyallenes LA, nitriles N and carboxylic acids CA leads to β-ketoenamides KE in good to excellent yields. The scope of this reaction is very broad and almost all types of nitriles and carboxylic acids have successfully been used. The alkoxy group introduced via the allene component is also variable and hence the subsequent transformation of this substituent into a hydroxy group can be performed under different conditions. Enantiopure nitriles or carboxylic acids can also be employed leading to chiral KE with high enantiopurity and dinitriles or dicarboxylic acids also lead to the expected bis-β-ketoenamides. β-Ketoenamides incorporate a unique combination of functional groups and hence a manifold of subsequent reactions to highly substituted heterocyclic compounds is possible. An intramolecular aldol-type condensation reaction efficiently furnishes pyridin-4-ols PY that can be further modified by palladium-catalyzed reactions, e.g., to specifically substituted furopyridine derivatives. Condensations of β-ketoenamides with ammonium salts or with hydroxylamine hydrochloride afford pyrimidines PM or pyrimidine N-oxides PO with a highly flexible substitution pattern in good yields. The functional groups of these heterocycles also allow a variety of subsequent reactions to various pyrimidine derivatives. On the other hand, acid-labile alkoxy substituents such as a 2-(trimethylsilyl)ethoxy group are required for the conversion of β-ketoenamides into 5-acetyl-substituted oxazoles OX, again compounds with high potential for subsequent functional group transformations. For acid labile β-ketoenamides bearing bulky substituents the acid treatment leads to acylamido-substituted 1,2-diketones DK that could be converted into quinoxalines QU. All classes of heterocycles accessed through the key β-ketoenamides show a unique substitution pattern – not easily accomplishable by alternative methods – and therefore many subsequent reactions are possible.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

Lechel

Kumar

Bera

et al. 2019

Beilstein J. Org. Chem.

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“…Reissig extensively investigated this type of reaction and discovered that it was highly diastereoselective, as shown in Scheme 5 [24][25][26].…”

Section: Addition Of Methoxyallenes To Nitronesmentioning

confidence: 99%

Oxazine ring construction: methods and applications to natural product synthesis

Wan

Joullié

2009

Front. Chem. China

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“…5,6 In this family, heterosubstituted and particularly acyclic alkoxyallenes have been the center of much interest [7][8][9] and can be used in many useful synthetic transformations. 10 In this context, we previously disclosed 11 a new domino C-O-cycloalkylation sequence allowing the facile one-pot preparation of hitherto unknown 2-vinylidenehydrofurans 1, which constituted the first stable cyclic version of an alkoxyallene with promising synthetic value (Scheme 1).…”

mentioning

confidence: 99%

“…The chemistry and synthetic applications of functionalized allenes have been the subject of extensive studies 1 involving both organic and organometallic chemistry [2][3][4] and still represent important fields of investigation in modern organic synthesis. 5,6 In this family, heterosubstituted and particularly acyclic alkoxyallenes have been the center of much interest [7][8][9] and can be used in many useful synthetic transformations. 10 In this context, we previously disclosed 11 a new domino C-O-cycloalkylation sequence allowing the facile one-pot preparation of hitherto unknown 2-vinylidenehydrofurans 1, which constituted the first stable cyclic version of an alkoxyallene with promising synthetic value (Scheme 1).…”

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confidence: 99%

Facile, Efficient and Chemoselective Palladium(0)-Catalyzed Isomerization of 2-Vinylidenehydrofurans into Valuable Functionalized 1,3-Dienes

Wavrin¹,

Nicolas²,

Viala³

et al. 2004

Synlett

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P a l l a d i u m ( 0 ) -C a t a l y z e d I s o m e r i z a t i o n o f 2 -V i n y l i d e n e h y d r o f u r a n s Abstract: Highly sensitive functionalized 2-vinylidene-hydrofurans undergo a facile, clean and chemoselective Pd(0)-catalyzed isomerization leading to stable and valuable 3-oxa-1,3-dienes precursor of polycyclic systems found in bioactive natural products through Diels-Alder reaction.

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Stereoselective syntheses of heterocycles with lithiated methoxyallene

Cited by 28 publications

References 40 publications

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

Oxazine ring construction: methods and applications to natural product synthesis

Facile, Efficient and Chemoselective Palladium(0)-Catalyzed Isomerization of 2-Vinylidenehydrofurans into Valuable Functionalized 1,3-Dienes

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