Ureidopeptide‐Based Brønsted Bases: Design, Synthesis and Application to the Catalytic Enantioselective Synthesis of β‐Amino Nitriles from (Arylsulfonyl)acetonitriles

Diosdado, Saioa; López, Rosa; Palomo, Claudio

doi:10.1002/chem.201304877

Cited by 48 publications

(19 citation statements)

References 119 publications

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“…4,5 These synthetic analogues are called peptidomimetics and are potentially used in catalysis, biosensors, electronic devices, and drug synthesis on the basis of their conducting and CT natures. 6,7 Peptidomimetics and their applications have been extensively studied using various experimental and theoretical methods. 8,9 Ureidopeptidomimetics (UPs) are one among synthetic peptidomimetics, 10 in which a peptide bond is replaced with a ureido group.…”

Section: ■ Introductionmentioning

confidence: 99%

Computational Studies on Structural, Excitation, and Charge-Transfer Properties of Ureidopeptidomimetics

2016

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Peptides with ureido group enclosing backbones are considered peptidomimetics and are known for their higher stabilities, biocompatibilities, antibiotic, inhibitor, and charge-transduction activities. These peptidomimetics have some unique applications, which are quite different from those of natural peptides. Hence, it is imperative to appreciate their properties at a microscopic level. In this regard, this work outlines, in detail, the charge transfer (CT) properties, holemigration dynamics, and electronic structures of various experimentally comprehended ureidopeptidomimetic models using density functional theory (DFT). Time-dependent DFT and complete active space self-consistent field computations on basic models provide the necessary evidence for the viability of CT from the end enfolding the ureido group to the other end with a carboxylate entity. This donor-to-acceptor CT has been reflected in excitation studies, in which the higher intensity band corresponds to CT from the π orbital of the ureido group to the π* orbital of the carboxylate entity. Further, hole-migration studies have shown that charge can evolve from the ureido end, whereas the hole generated at the carboxylate end does not migrate. However, hole migration has been reported to occur from both ends (amino and carboxylate ends) in glycine oligopeptides, and our studies show that the ability to transfer and migrate charge can be tuned by modifying the donor and acceptor functional groups in both the neutral and cationic charge states. We have analyzed the possibility of hole migration following ionization using DFT-based wave-packet propagation and found its occurrence on a ∼2−5 fs time scale, which reflects the charge-transduction ability of peptidomimetics.

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Section: ■ Introductionmentioning

confidence: 99%

Computational Studies on Structural, Excitation, and Charge-Transfer Properties of Ureidopeptidomimetics

2016

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“…The L ‐proline‐derived bifunctional thiourea 32 promotes the reaction of cyanoacetic acid with differently substituted isatins to produce enantiomerically enriched substituted 3‐hydroxyindoles in good yields after long reaction times (Scheme ) 51. 52 Although no mechanism has been proposed, it appears that 32 acts in a bifunctional manner by activating the keto function in the isatin substrate through hydrogen‐bond interactions with the thiourea whilst the tertiary amine facilitates pronucleophile deprotonation and final decarboxylation.…”

Section: The Use Of Synthetic Equivalentsmentioning

confidence: 99%

Cyanoalkylation: Alkylnitriles in Catalytic CC Bond‐Forming Reactions

2015

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Alkylnitriles are one of the most ubiquitous nitrogen-containing chemicals and are widely employed in reactions which result in nitrile-group conversion into other functionalities. Nevertheless, their use as carbon pronucleophiles in carbon-carbon bond-forming reactions has been hampered by difficulties associated mainly with the catalytic generation of active species, that is, α-cyano carbanions or metalated nitriles. Recent investigations have addressed this challenge and have resulted in different modes of alkylnitrile activation. This review illustrates these findings, which have set the foundation for the development of practical and conceptually new catalytic, direct cyanoalkylation methodologies.

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“…[49] Die Autoren schlagen einen Katalysezyklus vor,indem der Katalysator 26 zunächst zu 27 umgewandelt wird, das dann mit Cyanoessigsäure zu 28 reagiert. [51,52] Obwohl kein Mechanismus vorgeschlagen wurde, scheint der Katalysator difunktionell zu wirken, indem er die Ketofunktion im Isatinsubstrat durch Wasserstoffbrücken mit dem Thioharnstoff aktiviert, während das tertiäre Amin die Deprotonierung des Pronucleophils und die abschließende Decarboxylierung erleichtert. Die Reaktion von 29 mit dem Imin führt zu 30,das das b-Aminonitril liefert angesichts der hinreichenden Präzedenzfälle zu Palladium-Nitrilkomplexen nicht außer Acht gelassen werden.…”

Section: Verwendung Von Syntheseäquivalentenunclassified

“…Der in Schema 30 gezeigte,v on l-Prolin abgeleitete difunktionelle Thioharnstoff fçrdert die Reaktion von Cyanoessigsäure mit unterschiedlich substituierten Isatinen unter Bildung enantiomerenangereicherter substituierter 3-Hydroxyindole in guten Ausbeuten nach langen Reaktionszeiten. [51,52] Obwohl kein Mechanismus vorgeschlagen wurde, scheint der Katalysator difunktionell zu wirken, indem er die Ketofunktion im Isatinsubstrat durch Wasserstoffbrücken mit dem Thioharnstoff aktiviert, während das tertiäre Amin die Deprotonierung des Pronucleophils und die abschließende Decarboxylierung erleichtert.…”

Section: Verwendung Von Syntheseäquivalentenunclassified

Cyanoalkylierung: Alkylnitrile in katalytischen C‐C‐Kupplungen

López

Palomo

2015

Angewandte Chemie

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Alkylnitrile zählen zu den am weitesten verbreiteten stickstoffhaltigen Verbindungen, und sie werden vielfach in Reaktionen eingesetzt, die die Umwandlung der Nitrilgruppe in andere Funktionalitäten beinhalten. Ihre Verwendung als Kohlenstoff‐Pronucleophile in Kohlenstoff‐Kohlenstoff‐Kupplungen wurde jedoch durch Schwierigkeiten erschwert, die hauptsächlich mit der katalytischen Erzeugung aktiver Spezies wie α‐Cyanocarbanionen und/oder metallierter Nitrile im Zusammenhang stehen. In neuesten Untersuchungen wurden nun mehrere Aktivierungsarten für Alkylnitrile entwickelt. Dieser Kurzaufsatz veranschaulicht diese Erkenntnisse, die die Grundlage für praktische und konzeptionell neue katalytische direkte Cyanoalkylierungsmethoden bilden.

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Ureidopeptide‐Based Brønsted Bases: Design, Synthesis and Application to the Catalytic Enantioselective Synthesis of β‐Amino Nitriles from (Arylsulfonyl)acetonitriles

Cited by 48 publications

References 119 publications

Computational Studies on Structural, Excitation, and Charge-Transfer Properties of Ureidopeptidomimetics

Computational Studies on Structural, Excitation, and Charge-Transfer Properties of Ureidopeptidomimetics

Cyanoalkylation: Alkylnitriles in Catalytic CC Bond‐Forming Reactions

Cyanoalkylierung: Alkylnitrile in katalytischen C‐C‐Kupplungen

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