Reaktionen mit Chloracetaldehyd und 2.4‐Dichlor‐crotonaldehyd

Kopp, Erwin; Smidt, J.

doi:10.1002/jlac.19666930110

Cited by 13 publications

(2 citation statements)

References 8 publications

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“…The acetalization of glycerol with formaldehyde (route 1 in Scheme ) has been reported in the presence of different homogeneous acids, such as H 2 SO 4 , with or without solvent (reflux of benzene), − or PTSA at reflux of benzene with a yield of 90%. , Gras et al studied the acetalization and transacetalization of glycerol and formaldehyde or dimethyl or diethyl formal in the presence of LiBr and PTSA or HCl and obtained a mixture of dioxolane and dioxane in ratios of 60:40 and 44:56, respectively. When the transacetalization of dimethoxymethane was performed in the presence of PTSA and LiBr, a mixture of dioxolane and dioxane in a ratio of 6:94 was achieved, the transacetalization being especially selective toward the dioxane derivative.…”

Section: 14 Glycerolmentioning

confidence: 99%

Chemical Routes for the Transformation of Biomass into Chemicals

2007

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Section: 14 Glycerolmentioning

confidence: 99%

Chemical Routes for the Transformation of Biomass into Chemicals

2007

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“…Naheliegend war es daher, einen am S-Atom geschutzten Mercapto-acetaldehyd einzusetzen. Der von Kopp und Smith [7]…”

Section: Resultate Und Diskussionunclassified

Synthese von 2‐substituierten und 2,3‐disubstituierten Alkyl‐ und Aryl‐thiophenen und 2,3‐anellierten Thiophen‐Derivaten aus Ketonen als C₂‐Bausteine und Carbonodithiosäure‐O‐ethyl‐S‐(2‐oxoethyl)ester als C₂S‐Baustein

Aldvogel¹

1992

Helvetica Chimica Acta

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Synthesis of 2-Substituted and 2,3-Disubstituted Alkyl-und Aryl-thiophenes and Related 2,3-AnellatedThiophene Derivatives, Using Ketones and Carbonodithioic Acid 0-Ethyl S-(2-Oxoethyl) Ester as the Building Blocks A simple method to synthesize 2-substituted and 2,3-disubstituted alkyl-and aryl-thiophenes as well as related 2,3-anellated thiophenes 6, starting from ketones 1 as C2-fragment and the S-protected carbonodithionic-acid derivative 3 as a C2S-fragment is described. The aldols 4 are intermediates of the two step process.1. Einleitung. -Die zahlreichen in der Literatur beschriebenen Thiophen-Ringbildungsreaktionen fuhren mehrheitlich zu funktionalisierten Derivaten, wie z. B. Thiophen-aminen, -alkoholen oder -carbonsauren und ergeben oft hochsubstituierte Verbindungen [I]. Fur einfache Alkyl-oder Aryl-thiophene existieren dagegen nur wenige Methoden zur Ringbildung [2]; meist werden dabei Thiophen-carbonsauren als Zwischenprodukte durchlaufen, welche durch Decarboxylierung abgebaut werden miissen 131 141.

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The Tishchenko Reaction

Koskinen

Kataja

2015

Organic Reactions

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Aldehydes may be dimerized to symmetric esters via the Tishchenko reaction. This process is traditionally catalyzed by aluminum alkoxides, but a wide variety of different metal catalysts has been explored and implemented, ranging from simple alkali metal compounds to actinoid complexes. The mechanistic key step is a hydride transfer from a hemiacetal intermediate to an aldehyde, both participants being coordinated to the metal catalyst in the transition state. Recent research on the Tishchenko reaction has especially focused on the controlled synthesis of unsymmetrical esters. In the aldol‐Tishchenko variant, an aldol reaction takes place first between two aldehydes, or a ketone and an aldehyde. In the subsequent Tishchenko step, another aldehyde molecule coordinates to the aldol product, forming a hemiacetal intermediate. An intramolecular hydrogen transfer from the hemiacetal to the carbonyl group takes place, giving a 1,3‐diol monoester product. With ‐hydroxy ketone substrates, the reaction is highly diastereoselective towards 1,3‐ anti ‐diols due to a highly organized six‐membered transition state promoted by coordination of a metal catalyst to both the hemiacetal and carbonyl groups. Thus, recent research has strongly focused on the development of direct catalytic asymmetric aldol‐Tishchenko reactions. The Evans‐Tishchenko reaction is a further variant of the aldol‐Tishchenko reaction, being used to reduce preformed ‐hydroxy ketones to anti ‐1,3‐diols under relatively mild conditions. This method is applied to various total syntheses of natural products. Samarium iodide is commonly used as the catalyst, and nearly any aldehyde is suitable as the reducing agent. The reaction has also been exploited in a reverse fashion to oxidize complex aldehydes to carboxylic acids using a simple sacrificial ‐hydroxy ketone as the oxidant. This review covers the literature from the discovery of the Tishchenko reaction in 1887 up to early 2014. Different catalyst systems for both Tishchenko and aldol‐Tishchenko reactions are discussed and compared in the “Scope and Limitations” section, and the state of the art in substrate complexity for the reaction is presented in the “Tabular Survey”.

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Reaktionen mit Chloracetaldehyd und 2.4‐Dichlor‐crotonaldehyd

Cited by 13 publications

References 8 publications

Chemical Routes for the Transformation of Biomass into Chemicals

Chemical Routes for the Transformation of Biomass into Chemicals

Synthese von 2‐substituierten und 2,3‐disubstituierten Alkyl‐ und Aryl‐thiophenen und 2,3‐anellierten Thiophen‐Derivaten aus Ketonen als C₂‐Bausteine und Carbonodithiosäure‐O‐ethyl‐S‐(2‐oxoethyl)ester als C₂S‐Baustein

The Tishchenko Reaction

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Reaktionen mit Chloracetaldehyd und 2.4‐Dichlor‐crotonaldehyd

Cited by 13 publications

References 8 publications

Chemical Routes for the Transformation of Biomass into Chemicals

Chemical Routes for the Transformation of Biomass into Chemicals

Synthese von 2‐substituierten und 2,3‐disubstituierten Alkyl‐ und Aryl‐thiophenen und 2,3‐anellierten Thiophen‐Derivaten aus Ketonen als C2‐Bausteine und Carbonodithiosäure‐O‐ethyl‐S‐(2‐oxoethyl)ester als C2S‐Baustein

The Tishchenko Reaction

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Synthese von 2‐substituierten und 2,3‐disubstituierten Alkyl‐ und Aryl‐thiophenen und 2,3‐anellierten Thiophen‐Derivaten aus Ketonen als C₂‐Bausteine und Carbonodithiosäure‐O‐ethyl‐S‐(2‐oxoethyl)ester als C₂S‐Baustein