Catalytic Enantioselective 1,6‐Conjugate Addition of Grignard Reagents to Linear Dienoates

Hartog, Tim den; Harutyunyan, Syuzanna R.; Font, David García; Minnaard, Adriaan J.; Feringa, Ben L.

doi:10.1002/anie.200703702

Cited by 133 publications

(38 citation statements)

References 39 publications

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“…[192,193] So lieferte die konjugierte 1,6-Addition von Grignard-Reagentien an die Dienoate 91 mit einem Kupferkatalysator und dem Ferrocenylbisphosphan L22 als Liganden die 1,6-Addukte 92 mit guten Ausbeuten und ausgezeichneten Enantioselektivitäten (bis 96 % ee) (Schema 28). [192] Phosphoramidite ergaben hingegen bei der konjugierten 1,6-Addition an acyclische Substrate niedrige Enantioselektivitäten.…”

Section: Abfangen Von Reaktionszwischenstufen Mit Elektrophilenunclassified

Phosphoramidite: privilegierte Liganden in der asymmetrischen Katalyse

2010

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Die asymmetrische Katalyse mit Übergangsmetallkomplexen ist die Grundlage unzähliger stereoselektiver Umwandlungen und hat damit das Bild der modernen Synthesechemie gewandelt. Der Schlüssel zum Erfolg war die Entwicklung chiraler Liganden zur Kontrolle der Regio‐, Diastereo‐ und Enantioselektivität. Dabei haben sich Phosphoramidite als eine äußerst vielseitige und leicht zugängliche Klasse von chiralen Liganden erwiesen. Ihre modulare Struktur ermöglicht die Herstellung von Ligandenbibliotheken und erleichtert die Feinabstimmung für eine bestimmte katalytische Reaktion. Phosphoramidite bewirken oft außerordentlich hohe Stereoselektivitäten, und ihre einzähnige Natur ist in der kombinatorischen Katalyse, die gemischte Liganden verwendet, unverzichtbar. In diesem Aufsatz werden neue Entwicklungen in der asymmetrischen Katalyse mit Phosphoramiditen diskutiert, wobei der Schwerpunkt auf der Bildung von Kohlenstoff‐ Kohlenstoff‐ und Kohlenstoff‐Heteroatom‐Bindungen liegt.

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Section: Abfangen Von Reaktionszwischenstufen Mit Elektrophilenunclassified

Phosphoramidite: privilegierte Liganden in der asymmetrischen Katalyse

2010

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“…Subsequently, Feringa et al. disclosed the highly enantioselective and regioselective addition of Grignard reagents to dienoates 25. Excellent 1,6 selectivity and high stereocontrol were reported thanks to ferrocene‐based phosphine ligands and CuBr ⋅ Me 2 S as the catalyst combination.…”

Section: Introductionmentioning

confidence: 99%

Formation of Quaternary Stereogenic Centers by NHC–Cu‐Catalyzed Asymmetric Conjugate Addition Reactions with Grignard Reagents on Polyconjugated Cyclic Enones

Tissot

Poggiali

Henon

et al. 2012

Chemistry A European J

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The copper-catalyzed conjugate addition of various Grignard reagents to polyconjugated enones (dienone and enynone derivatives) is reported. The catalyst system, composed of copper triflate and an NHC ligand, led to the unusual selective formation of the 1,4-addition products. This reaction allows for the creation of all-carbon chiral quaternary centers with enantiomeric excesses up to 99%. The remaining unsaturation on the 1,4 adducts give access to valuable synthetic transformations.

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“…However, catalytic enantioselective 1,6-conjugate additions are uncommon, and ones that are able to incorporate readily functionalizable moieties, such as propargyl or allyl groups, into acyclic α,β,γ,δ-doubly unsaturated acceptors are unknown 2 . Chemical transformations that could generate a new bond at the C6 position of a dienoate are particularly desirable, as the resulting products would be subjected to further modifications; such reactions, especially when dienoates contain two equally substituted olefins, are scarce 3 and are confined to reactions promoted by a phosphine–copper (with alkyl Grignard 4,5 , dialkylzinc or trialkylaluminum compounds 6,7 ), a diene–iridium (with arylboroxines) 8,9 , and a bisphosphine–cobalt catalyst (with monosilyl-acetylenes) 10 . 1,6-conjugate additions are otherwise limited to substrates where there is full substitution at C4 11 .…”

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Catalytic enantioselective 1,6-conjugate additions of propargyl and allyl groups

Meng

Torker

et al. 2016

Nature

120

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Conjugate (or 1,4-) additions of carbanionic species to α,β-unsaturated carbonyl compounds are vital to research in organic and medicinal chemistry, and there are several known chiral catalysts that facilitate the catalytic enantioselective additions of nucleophiles to enoates1. However, catalytic enantioselective 1,6-conjugate additions are uncommon, and ones that are able to incorporate readily functionalizable moieties, such as propargyl or allyl groups, into acyclic α,β,γ,δ-doubly unsaturated acceptors are unknown2. Chemical transformations that could generate a new bond at the C6 position of a dienoate are particularly desirable, as the resulting products would be subjected to further modifications; such reactions, especially when dienoates contain two equally substituted olefins, are scarce3 and are confined to reactions promoted by a phosphine–copper (with alkyl Grignard4,5, dialkylzinc or trialkylaluminum compounds6,7), a diene–iridium (with arylboroxines)8,9, and a bisphosphine–cobalt catalyst (with monosilyl-acetylenes)10. 1,6-conjugate additions are otherwise limited to substrates where there is full substitution at C411. It is not clear why certain catalysts favor bond formation at C6, and – while there are a small number of catalytic enantioselective conjugate allyl additions12,13,14,15 – related 1,6-additions and processes involving a propargyl unit are non-existent. In this manuscript, we show that an easily accessible organocopper catalyst can promote 1,6-conjugate additions of propargyl and 2-boryl-substituted allyl groups to acyclic dienoates with high selectivity. A commercially available allenylboron compound or a monosubstituted allene may be used. Products can be obtained in up to 83 percent yield, >98 percent diastereo- (for allyl additions) and 99:1 enantiomeric ratio. Mechanistic details, including the origins of high site- (1,6- versus 1,4-) and enantioselectivity as a function of the catalyst structure and reaction type, have been elucidated by means of density functional theory (DFT) calculations.

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Catalytic Enantioselective 1,6‐Conjugate Addition of Grignard Reagents to Linear Dienoates

Cited by 133 publications

References 39 publications

Phosphoramidite: privilegierte Liganden in der asymmetrischen Katalyse

Phosphoramidite: privilegierte Liganden in der asymmetrischen Katalyse

Formation of Quaternary Stereogenic Centers by NHC–Cu‐Catalyzed Asymmetric Conjugate Addition Reactions with Grignard Reagents on Polyconjugated Cyclic Enones

Catalytic enantioselective 1,6-conjugate additions of propargyl and allyl groups

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