Ketene Three‐Component Reaction: A Metal‐Free Multicomponent Approach to Stereodefined Captodative Olefins

Basso, Andrea; Banfi, Luca; Garbarino, Silvia; Riva, Renata

doi:10.1002/anie.201209399

Cited by 35 publications

(22 citation statements)

References 21 publications

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“…Recently, there has been interest in using “non‐traditional” partners in multicomponent Passerini and Ugi reactions, partners including, as the acid component thioacetic acids and hexafluoro isopropanol, and as carbonyl components ketenes, and TiCl 4 ‐mediated thiocarbenium species . These non‐traditional components have advantages in that they lead to unique functional moieties beyond the typical amide and ester linkages in a single step that would otherwise require multiple (indirect) steps to access.…”

Section: Methodsmentioning

confidence: 99%

Visible‐Light‐Induced Passerini Multicomponent Polymerization

et al. 2019

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Herein, we introduce an additive-free visible-lightinduced Passerini multicomponent polymerization (MCP) for the generation of high molar mass chains.Inplace of classical aldehydes (or ketones), highly reactive,insitu photogenerated thioaldehydes are exploited along with isocyanides and carboxylic acids.P rone to side reactions,t he thioaldehyde moieties create ac omplex reaction environment which can be tamed by optimizing the synthetic conditions utilizing stochastic reaction path analysis,h ighlighting the potential of semibatch procedures.O nce the complex MCP environment is understood, step-growth polymers can be synthesized under mild reaction conditions which-after aM umm rearrangement-result in the incorporation of thioester moieties directly into the polymer backbone,leading to soft matter materials that can be degraded by straightforwarda minolysis or chain expanded by thiirane insertion.

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Section: Methodsmentioning

confidence: 99%

Visible‐Light‐Induced Passerini Multicomponent Polymerization

et al. 2019

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“…The tactic to expand the scope of Passerini reaction was to use surrogates of the carbonyl partners. As described in Scheme , syn ‐chlorooximes, diazoketones, alcohols, azirines and isatins could be employed instead of aryl or alkyl aldehydes (Scheme ). Besides, in 2018, Zhang and co‐workers have firstly reported asymmetric phosphoric acid‐catalyzed four‐component Ugi reaction, which solved the long‐standing stereochemical challenges of the Ugi reaction.…”

Section: Electrophilic Acidsmentioning

confidence: 99%

Arylacetic Acids in Organic Synthesis

et al. 2019

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Arylacetic acids are widely used in organic reactions and their recent advances are summarized in six categories according to their triggered pathways: (1) the acid as directing group in ortho-or meta-CÀ H activation; (2) decarboxylation; (3) deprotonation; (4) nucleophilic methylenes; (5) nucleophilic acids; (6) electrophilic acids. Reactions with alkenes, alkynes, aldehydes, amines, water, Grignard reagents, silanes and so forth are discussed. We hope this Minireview will promote future research in this area. Recently, the Zeng group [3g] reported a weakly coordinationassisted alkynylation of arylacetic acids with iridium catalysis under air atmosphere (Eq. 2-2). It was supported the sixmembered ring cycloiridiated 2.5 acted as the key intermediate. The alkynylation of indole, thiophene, pyrrole, and benzo[b] thiophene afforded better yields than phenylacetic acids. The acid moiety could also participated in the intramolecular ortho-CÀ H activation, which was developed by the Shi group to obtain lactonization 2.6 (Eq. 2-3) (Scheme 2). Meta-CÀ H ArylationThe study of Yu group [3e] in 2017 revealed a successful control of meta selectivity 3.1 of arylation from aryl iodides (Eq. 3-1). The use of mono-protected 3-amino-2-hydroxypyridine (as ligand) and 2-carbomethoxynorbornene (NBE-CO 2 Me) were crucial. In the absence of NBE-CO 2 Me, only ortho-arylated product was obtained. This method was still efficient in a gramsale (Scheme 3). Decarboxylation Decarboxylative CouplingAs shown in Scheme 4, the decarboxylation could generate benzyl radicals 4.1. Then, direct couplings of 4.1 with diverse [ + ] These authors contributed equally. Scheme 1. Six categories based on triggered mechanism. 2 3 4 5 6 7 8 . Passerini Three-Component ReactionThe Passerini reaction was the oldest multicomponent reaction (MCR) [37d] in which isocyanides, carboxylic acids and aldehydes were used. It was powerful for the rapid construction of complex molecules. The tactic to expand the scope of Passerini reaction was to use surrogates of the carbonyl partners. As described in Scheme 51, syn-chlorooximes, [37b] diazoketones, [37c] alcohols, [37d,e] azirines [37f] and isatins [37g] could be employed instead of aryl or alkyl aldehydes [37a] (Scheme 51). Besides, in 2018, Zhang and co-workers [37] have firstly reported asymmetric phosphoric acid-catalyzed four-component Ugi reaction, which Scheme 45. BTM-catalyzed cycloaddition. Scheme 46. HBTM-catalyzed cycloaddition. Scheme 47. TFA-catalyzed reaction. Scheme 48. Friedel-Crafts triggered tandem reactions. Scheme 49. C-acylation of 1,3-diones. Scheme 50. C-acylation of 1,3-indandiones.

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“…Bei der Keten‐Dreikomponentenreaktion (K‐3CR) wurden reaktive Ketene 14 photochemisch über eine Wolff‐Umlagerung von Diazoketonen 12 gebildet und in situ mit einem Isocyanid und einer Carbonsäure umgesetzt, wobei Olefine 13 a – c entstanden (Schema ); der Mechanismus ähnelte dem der Passerini‐Reaktion. Die photochemische Bildung von 14 benötigte keine Basen, die üblicherweise unter thermischen Bedingungen gebraucht werden und inkompatibel mit der MCR wären . Bemerkenswerterweise konnte die Reaktion auch unter kontinuierlichen Bedingungen durchgeführt werden, was in einer erhöhten Stereomerenreinheit der Produkte und verkürzter Verweildauer resultierte (Schema )…”

Section: Photochemische Mehrkomponentenreaktionenunclassified

Photoinduzierte Mehrkomponentenreaktionen

et al. 2016

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Die Kombination von Mehrkomponentenansätzen mit lichtgetriebenen Prozessen erschließt neue Bereiche auf dem Gebiet der organischen Synthesechemie, deren Bedarf an nachhaltigen und atom‐ sowie energieeffizienten Reaktionen immer dringlicher wird. Photoinduzierte Mehrkomponentenreaktionen befinden sich noch immer in einem frühen Stadium, für die nahe Zukunft ist jedoch mit deutlichen Fortschritten zu rechnen.

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Ketene Three‐Component Reaction: A Metal‐Free Multicomponent Approach to Stereodefined Captodative Olefins

Abstract: Scheme 1. General multicomponent approach to captodative olefins 1. FG = functional group.Scheme 2. Comparison between a) the previously reported method [7] and b) the new Passerini-like multicomponent reactions with arylketenes as carbonyl surrogates.

Cited by 35 publications

References 21 publications

Visible‐Light‐Induced Passerini Multicomponent Polymerization

Visible‐Light‐Induced Passerini Multicomponent Polymerization

Arylacetic Acids in Organic Synthesis

Photoinduzierte Mehrkomponentenreaktionen

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