Synthesis of Vicinal Aminoalcohols by Stereoselective Aza‐Wacker Cyclizations: Access to (−)‐Acosamine by Redox Relay

Weinstein, Adam B.; Schuman, David P.; Tan, Zhi Xu; Stahl, Shannon S.

doi:10.1002/anie.201305926

Cited by 66 publications

(34 citation statements)

References 53 publications

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“…This moiety is usually accessible by transition-metal catalysis,a nd the amination of tri-and tetrasubstituted olefins is difficult. [126] Thed iastereoselectivity of the reaction was high, and the scope broad.…”

Section: Electrochemical Synthesis Of Heterocyclesmentioning

confidence: 99%

Elektrifizierung der organischen Synthese

et al. 2018

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Die direkte Nutzung von Elektrizität für die organische Synthese erlebt derzeit eine Renaissance. Von den eher syntheseorientierten Laboratorien, die auf diesem Gebiet arbeiten, werden neuartige oder althergebrachte Konzepte genutzt, um den Weg von der Nischentechnologie zu breiteren Anwendungen zu ebnen. Da nur Elektronen als Reagens genutzt werden, wird die Bildung von Abfallreagentien effizient vermieden. Darüber hinaus können stöchiometrische Reagentien regeneriert werden und ermöglichen eine elektrokatalysierte Umsetzung. Die Anwendung von elektroorganischen Transformationen ist jedoch mehr als nur die Minimierung des Abfallaufkommens; sie führt vielmehr zu inhärent sicheren Prozessen, zur Abkürzung vieler Synthesestufen, zu milderen Reaktionsbedingungen, zu alternativen Zugängen zu gewünschten Struktureinheiten sowie zur Schaffung neuer Bereiche für geistiges Eigentum (Patente). Wenn die verwendete Elektrizität aus regenerativen Ressourcen stammt, kann dieser Stromüberschuss direkt als terminales Oxidations‐ oder Reduktionsmittel eingesetzt werden, was eine äußerst nachhaltige und damit hochattraktive Technologie darstellt. Dieser Aufsatz gibt einen Überblick über die jüngsten Entwicklungen auf dem Gebiet der elektrochemischen Synthese, welche die Zukunft dieses stark aufstrebenden Gebietes beeinflussen werden.

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Section: Electrochemical Synthesis Of Heterocyclesmentioning

confidence: 99%

Elektrifizierung der organischen Synthese

et al. 2018

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“…Expeditious and stereoselective synthetic methodologies for chiral amino‐alcohols from simple starting materials are of significant interest (Shi, Wong, & Buchwald, 2016; Weinstein, Schuman, Tan, & Stahl, 2013). Chiral amino‐alcohol moieties occur naturally in a large number of biologically active compounds and are synthesized for various applications such as new‐to‐nature pharmaceuticals, key industrial synthons for the production of complex molecules and optically pure pharmaceuticals, that is, HIV protease inhibitors (Kaldor et al, 1997; Kwon & Ko, 2002) or ephedrine‐type structures produced via multi‐step reactions as recently described by Sehl, Maugeri, and Rother (2015a).…”

Section: Introductionmentioning

confidence: 99%

Enzymatic synthesis of chiral amino‐alcohols by coupling transketolase and transaminase‐catalyzed reactions in a cascading continuous‐flow microreactor system

Gruber

Carvalho

Marques

et al. 2017

Biotech & Bioengineering

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Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino‐alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)‐2‐amino‐1,3,4‐butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non‐chiral starting materials, by coupling a transketolase‐ and a transaminase‐catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor‐based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous‐flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase‐catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml−1. Following optimization of the transaminase‐catalyzed reaction, a volumetric activity of 10.8 U ml−1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous‐flow microreactors can be applied for the design and optimization of biocatalytic processes.

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“…In recent years, various late transition metal catalysts such as Pd [38][39][40][41], Ru [42], Rh [43], Ir [44], and Cu [45] have been applied in sp 2 C-H bond amination. Within this methodology, Pd-catalyzed intramolecular azaWacker-type oxidative reactions represent one crucial route to produce a range of 5-membered Ncontaining heterocycles [46][47][48][49][50][51]. However, intermolecular aza-Wacker-type oxidative amination has been rarely reported and protection of the amine nitrogen is often required in the reaction because palladium species would be deactivated via coordination of the unprotected amine to the metal center in most cases [41,[52][53][54].…”

Section: Introductionmentioning

confidence: 99%

Practical Pd(TFA)2-Catalyzed Aerobic [4+1] Annulation for the Synthesis of Pyrroles via “One-Pot” Cascade Reactions

Mang

Yang

et al. 2016

Catalysts

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Abstract:The Pd(TFA) 2 -catalyzed [4+1] annulation of chained or cyclic α-alkenyl-dicarbonyl compounds and unprotected primary amines for "one-pot" synthesis of pyrroles is reported here. Enamination and amino-alkene were involved in this practical and efficient tandem reaction. The annulation products were isolated in moderate to excellent yields with O 2 as the terminal oxidant under mild conditions. In addition, this method was applied to synthesize highly regioselective aminomethylated and di(1H-pyrrol-3-yl)methane products.

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Synthesis of Vicinal Aminoalcohols by Stereoselective Aza‐Wacker Cyclizations: Access to (−)‐Acosamine by Redox Relay

Cited by 66 publications

References 53 publications

Elektrifizierung der organischen Synthese

Elektrifizierung der organischen Synthese

Enzymatic synthesis of chiral amino‐alcohols by coupling transketolase and transaminase‐catalyzed reactions in a cascading continuous‐flow microreactor system

Practical Pd(TFA)2-Catalyzed Aerobic [4+1] Annulation for the Synthesis of Pyrroles via “One-Pot” Cascade Reactions

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