Catalyst‐Controlled Wacker‐Type Oxidation of Protected Allylic Amines

Michel, Brian W.; McCombs, Jessica R.; Winkler, Andrea; Sigman, Matthew S.

doi:10.1002/ange.201004156

Cited by 23 publications

(20 citation statements)

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“…[16] This finding demonstrates the important and general role of inductive effects on nucleopalladation regioselectivity, as, to our knowledge, these results comprise the first examples of achieving a formally anti-Markovnikov Wacker oxidation using inductive effects to reverse the Markovnikov selectivity. [17] In conclusion, trifluoromethyl groups were shown to be highly efficient directing groups for Wacker-type oxidations, thereby enabling facile access to b-trifluoromethyl-substituted ketones. The broad functional-group tolerance of the oxidation, combined with the readily accessible starting materials, bodes well for the immediate application of the method.…”

Section: Methodsmentioning

confidence: 99%

“…Under Wacker conditions, terminal alkenes are oxidized with high selectivity to methyl ketones, in accordance with Markovnikovs rule. [17] In conclusion, trifluoromethyl groups were shown to be highly efficient directing groups for Wacker-type oxidations, thereby enabling facile access to b-trifluoromethyl-substituted ketones. Thus, 4,4,4trifluoro-1-butene was subjected to both our standard reaction conditions as well as the classical Tsuji-Wacker conditions (Scheme 3).…”

mentioning

confidence: 89%

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Rapid Access to β‐Trifluoromethyl‐Substituted Ketones: Harnessing Inductive Effects in Wacker‐Type Oxidations of Internal Alkenes

et al. 2014

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We present a practical trifluoromethyl-directed Wacker-type oxidation of internal alkenes that enables rapid access to b-trifluoromethyl-substituted ketones. Allylic trifluoromethyl-substituted alkenes bearing a wide range of functional groups can be oxidized in high yield and regioselectivity. The distance dependence of the regioselectivity was established by systematic variation of the number of methylene units between the double bond and the trifluoromethyl group. The regioselectivity enforced by traditional directing groups could even be reversed by introduction of a competing trifluoromethyl group. Besides being a new powerful synthetic method to prepare fluorinated molecules, this work directly probes the role of inductive effects on nucleopalladation events. Scheme 1. Regiocontrol in Wacker oxidations of internal alkenes. BQ = p-benzoquinone.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 89%

Rapid Access to β‐Trifluoromethyl‐Substituted Ketones: Harnessing Inductive Effects in Wacker‐Type Oxidations of Internal Alkenes

et al. 2014

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“…This protocol featured a short reaction time, broad substrate scope, and environmental advantages. Subsequently, this Pd(Quinox)–TBHP catalyst system was further applied for the oxidation of protected allylic amines …”

Section: H2o2 or Tbhp As The Oxidantmentioning

confidence: 99%

Palladium‐Catalyzed Oxidation Reactions of Alkenes with Green Oxidants

Jiang

2019

ChemSusChem

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Transition‐metal‐catalyzed oxidative functionalization of alkenes has emerged as a powerful and valuable tool in modern organic synthesis. Recently, many methods have been established for the assembly of C−C and C–heteroatom bonds, which provides tremendous possibility for application in biology, medicine, and materials science. However, the use of stoichiometric amounts of strong oxidants leads to poor selectivity, low atom economy, and a series of undesired waste products. By contrast, green oxidants, such as O2, H2O2, or tert‐butyl hydroperoxide (TBHP), have bright prospects due to their attributes of mild, low cost, and great sustainability in transition‐metal‐catalyzed oxidation reactions. Based on the great and unique potential for the development of aerobic reactions, this review mainly highlights homogenous palladium‐catalyzed green oxidations of alkenes that have been reported in recent years. These methods provide new strategies for the transformation and functionalization of alkenes; some of them have also been successfully applied to the synthesis of the core structures of drugs and natural products. Additionally, through in‐depth studies of the reaction mechanisms in this field, it is believed that palladium‐catalyzed green oxidation reactions of alkenes with O2, H2O2, or TBHP will create added value for organic synthetic chemistry.

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“…[57] Noch eindrucksvoller ist die Feststellung von Sigman et al, dass der spezifisch abgestimmte Pd-Komplex 30, kombiniert mit dem Gebrauch von tBuOOH als Oxidationsmittel, zu fast vollständiger Selektivität für das Markownikoff-Keton führt, was einem exquisiten ligandengesteuerten Prozess gleichkommt. [58] Detaillierte kinetische Studien und die Synthese von elektronisch ausgeprägten Ligandengerüsten legen die Vermutung nahe, dass ein hochorganisierter kationischer Pd-Alken-Komplex wie 31 für die hohe beobachtete Selektivität verantwortlich ist. [59] Stahl et al entwickelten eine Aza-Wacker-Reaktion unter Verwendung von O 2 als terminalem Oxidationsmittel als eine hoch Markownikoff-selektive Methode zur Herstellung von Enaminen aus einfachen Alkenen und Aminen (Schema 18 a).…”

Section: Regioselektive Funktionalisierung Von Alkenenunclassified

Katalytische selektive Synthese

2012

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Der Verlauf und das Produkt einer Reaktion lassen sich gezielt über die Katalysatorstruktur steuern, selbst bei nahezu identischen Reaktionsbedingungen. Katalysatorkontrollierte Selektivität ist in der enantioselektiven Synthese gut etabliert, in katalytischen regio‐, chemo‐ und produktselektiven Reaktionen aber wenig verbreitet. Dieser Aufsatz beschreibt, wie eine Ausgangsverbindung lediglich durch die Auswahl des Katalysators selektiv in zwei oder mehr unterschiedliche Produkte umgewandelt werden kann. Wir stellen Beispiele selektiver Katalysen vor und hoffen, dass die bisher erzielten Fortschritte ermutigend für das Gebiet sind. Zugleich wollen auch die noch offenen Fragen beim Entwurf und dem mechanistischen Verständnis selektiver Katalysatoren thematisieren.

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Catalyst‐Controlled Wacker‐Type Oxidation of Protected Allylic Amines

Abstract: Scheme 2. a) Examination of the retention of enantiomeric excess and b) comparison to the Tsuji-Wacker oxidation. Angewandte Chemie

Cited by 23 publications

References 22 publications

Rapid Access to β‐Trifluoromethyl‐Substituted Ketones: Harnessing Inductive Effects in Wacker‐Type Oxidations of Internal Alkenes

Rapid Access to β‐Trifluoromethyl‐Substituted Ketones: Harnessing Inductive Effects in Wacker‐Type Oxidations of Internal Alkenes

Palladium‐Catalyzed Oxidation Reactions of Alkenes with Green Oxidants

Katalytische selektive Synthese

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