Name: highly stereoselective synthesis of 1,6-ketoesters mediated by ionic liquids: a three-component reaction enabling rapid access to a new class of low molecular weight gelators
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1. Gram-skala Syntese af methyl-6-oxo-3,4,6-triphenylhexanoate <ol><li> Dry 1-ethyl-3-methyl imidazolium acetat (EMIMAc) i en rundbundet kolbe på en rotationsfordamper ved 10 mbar, 40 ° C i 1 time. </li><li> Tilføj 2,1 g tørt EMIMAc og 1,0 g 1,3-diphenyl-2-propen-1-on Til en 100 ml rundbundet kolbe udstyret med en magnetomrører. </li><li> Tilføj 2.019 ml methanol og 2,3 g kanelaldehyd til kolben. </li><li> Ved stuetemperatur (22 ° C) opløses blandingen i 60 ml dichlormethan ved omrøring i 1 min. </li><li> Der...

<ol>
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X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organocatalytic+upgrading+of+the+key+biorefining+building+block+by+a+catalytic+ionic+liquid+and+N-heterocyclic+carbenes.">Organocatalytic upgrading of the key biorefining building block by a catalytic ionic liquid and N-heterocyclic carbenes.</a> Green Chem. 14, 2738-2746 (2012).</li><li>Ta, L., Axelsson, A., Bijl, J., Haukka, M., Sund&#233;n, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ionic+Liquids+as+Precatalysts+in+the+Highly+Stereoselective+Conjugate+Addition+of+&#945;,&#946;-Unsaturated+Aldehydes+to+Chalcones.">Ionic Liquids as Precatalysts in the Highly Stereoselective Conjugate Addition of &#945;,&#946;-Unsaturated Aldehydes to Chalcones.</a> Chem. Eur. 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Baseret på anti-konfigurationen bestemmes ved røntgenanalyse af ketoester 3 og på den mekanistiske undersøgelser foreslået af Bode og medarbejdere 30 den følgende reaktion vej foreslås (figur 5). Deprotonering af IL genererer NHC arter; NHC reagerer med umættede aldehyd til dannelse af Breslow mellemprodukt I. Breslow mellemproduktet og chalcon reagere på en cross-benzoin reaktion til dannelse dien II. Intermediate II gennemgår en oxy-Cope omordning via båd overgang tilsta...

<img alt="TOC 1" src="/files/ftp_upload/53213/53213TOC.jpg" /> (Ovenfor) trekomponent syntese af 1,6-ketoestere: en ny klasse af lavmolekylære gelators. Ioniske væsker (ILS) har høj stabilitet, lav flygtighed, ikke-brændbarhed og har derfor gjort opmærksom som sikre reaktion medier og ideelle opløsningsmidler til genbrug. 1-3 dialkyl imidazoliums er en bestemt type af ioniske væsker, i nærværelse af en base , kan deprotoneres at gøre en N-heterocykliske carben (NHC). 4 På organocatalysis, NHCs, der opererer under forskellige reaktionsveje, har fundet udbredt brug i en bred vifte af generiske reaktioner. 5-11 På trods af dette, forbindelsen mellem IL&#39;er og CC obligation forming NHC-katalyse er relativt uudforsket. Alligevel har NHCs afledt af IL&#39;er blevet rapporteret at katalysere CC bindingsdannende reaktioner såsom benzoin kondensation og Stetter reaktionen. 12-22 For eksempel Davis et al. Har vist, at IL&#39;er afledt af N-alkyl thiazoliums tjene som precatalysts i dannelse af benzoin fra benzaldehyd. 12 Mere for nylig, Chen og medarbejdere udvidet dette begreb under anvendelse af en imidazolium baseret IL, 1-ethyl-3-methyl imidazolium acetat (EMIMAc) at foretage benzoin kondens på 5-hydroxymethylfurfural (HMF) for at generere 5,5 &#39;-di (hydroxymethyl) furoin (DHMF). 23. Eftersom IL&#39;er er kommercielt tilgængelige og tilbyde en billig måde at generere NHCs, vi var interesserede i at undersøge, hvad andre typer af reaktioner IL&#39;er kunne udføre. Til dette formål, fandt vi, at dialkylsulfater imidazoliums effektivt kunne anvendes som precatalysts i den formelle konjugat additipå umættede aldehyder af at chalconer (figur 1), hvilket gav 1,6-ketoestere. Den mest effektive IL, EMIMAc, fremmer en meget stereoselektiv reaktion mellem cinnamaldehyd og chalcon. Reaktionen sker med stor præference for anti -diastereomeren og 1,6-ketoestere kan isoleres i udbytter på op til 92%. 24,25,26 <img alt="Figur 1" src="/files/ftp_upload/53213/53213fig1.jpg" /> Figur 1: IL-medieret trekomponent, stereoselektiv tilsætning af cinnamaldehyd til chalcon.

<table>
	<tbody>
		<tr>
			<td>1-ethyl-3-methyl imidazolium acetate</td>
			<td>Aldrich</td>
			<td>51053-100G-F</td>
			<td>Produced by BASF &#8805;90%, dried on a rotary evaporated before use (10 mBar, 40 &#176;C, 1h) 
			CAS NUMBER: 143314-17-4</td>
		</tr>
		<tr>
			<td>1,3-diphenyl-2-propen-1-one</td>
			<td>Aldrich</td>
			<td>11970-100G</td>
			<td>98.0% 
			CAS NUMBER: 94-41-7</td>
		</tr>
		<tr>
			<td>trans-cinnamaldehyde&#160;</td>
			<td>Aldrich</td>
			<td>C80687-25G</td>
			<td>99%, stored under nitrogen prior to use 
			CAS NUMBER: 14371-10-9</td>
		</tr>
		<tr>
			<td>1,8-Diazobicyclo[5.4.0]undec-7-ene</td>
			<td>Aldrich</td>
			<td>139009-25G</td>
			<td>98% 
			CAS NUMBER: 6674-22-2</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Aldrich</td>
			<td>32213N-2.5L</td>
			<td>puriss. P.a., ACS reagent, reag. ISO, reag. Ph. Eur. &#8805;99.8% (GC) 
			CAS NUMBER: 67-56-1</td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>Fischer Chemical</td>
			<td>D/1852/17X</td>
			<td>Analytic reagent grade, stabilized with amylene 
			CAS NUMBER:9/2/1975</td>
		</tr>
		<tr>
			<td>n-Heptane</td>
			<td>Fischer Chemical</td>
			<td>H/0160/17X</td>
			<td>Analytic reagent grade 
			CAS NUMBER: 142-82-5</td>
		</tr>
	</tbody>
</table>

highly stereoselective synthesis of 1,6-ketoesters mediated by ionic liquids: a three-component reaction enabling rapid access to a new class of low molecular weight gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of &#945;,&#946;-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

Som eksemplificeret ovenfor, EMIMAc tjene som prækatalysator i den formelle konjugat tilsætning af α, β-umættet aldehyd til chalconer. Andre kommercielt tilgængelige imidazoliumsalte baseret IL&#39;er, såsom 1-ethyl-3-methylimidazolium chloride (EMIMCl) og 1-butyl-3-methylimidazolium chloride (BMIMCl) blev også undersøgt, men disse reaktioner udviklet sig i lavere udbytter indikerer, at acetatanion kan være 27,28 * vigtige for reaktivitet (tabel 1, post 1-3). <p...

Watch this Scientific Journal Video about Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

Meget Stereoselektiv Syntese af 1,6-Ketoestere medieret af ioniske væsker: en tre-komponent Reaktion Aktivering hurtig adgang til en ny klasse af lavmolekylære Gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form ...

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Fremstilling og anvendelse af Samarium Diiodide (SMI<sub&gt; 2</sub&gt;) I Organic Synthesis: Den mekanistiske rolle HMPA og Ni (II) salte i Samarium Barbier Reaction

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Facile Syntese af ormelignende Miceller af synligt lys Mediated Dispersion polymerisering Brug Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Fra molekyler til materialer: Engineering nye ionisk væske krystaller gennem Halogen limning

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Fabrikation og afprøvning af katalytisk aerogeler fremstillet Via Rapid superkritisk ekstraktion

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

Hurtig Nanoprobe Signal forstærkning af In Situ guld nanopartikel syntese

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...