Highly Selective Synthesis of a 1,3,5‐Tris‐Protected Calix[6]arene‐Type Molecular Platform through Coordination and Host–Guest Chemistry
Identifieur interne : 000D16 ( Istex/Corpus ); précédent : 000D15; suivant : 000D17Highly Selective Synthesis of a 1,3,5‐Tris‐Protected Calix[6]arene‐Type Molecular Platform through Coordination and Host–Guest Chemistry
Auteurs : Stéphane Le Ac ; Jérôme Marrot ; Ivan JabinSource :
- Chemistry – A European Journal [ 0947-6539 ] ; 2008-04-07.
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- KwdEn :
Abstract
An elegant methodology based on the synergistic combination of coordination and host–guest chemistry led to the highly efficient synthesis of a unique C3v‐symmetrical, calix[6]arene‐based molecular platform with three protected amino arms in alternating positions. The key step involves the formation of a stable supramolecular host–guest ZnII complex from a C6v‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the ZnII ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the C3v‐symmetrical complex in such a way that the uncoordinated NH2 groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc2O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a C3v‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. Examples of such readily available C3v‐symmetrical calixarene‐based building blocks are extremely rare in the literature.
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DOI: 10.1002/chem.200701770
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The key step involves the formation of a stable supramolecular host–guest ZnII complex from a C6v‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the ZnII ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the C3v‐symmetrical complex in such a way that the uncoordinated NH2 groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc2O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a C3v‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. Examples of such readily available C3v‐symmetrical calixarene‐based building blocks are extremely rare in the literature.</div></front></TEI><istex><corpusName>wiley</corpusName><author><json:item><name>Stéphane Le Gac Dr.</name><affiliations><json:string>URCOM, Université du Havre, Faculté des Sciences et Techniques, 25 rue Philippe Lebon, BP 540, 76058 Le Havre cedex, France</json:string></affiliations></json:item><json:item><name>Jérôme Marrot Dr.</name><affiliations><json:string>Institut Lavoisier, UMR CNRS 8180, Université de Versailles St‐Quentin en Yvelines, 45 av. des Etats‐Unis, 78035 Versailles cedex, France</json:string></affiliations></json:item><json:item><name>Ivan Jabin Prof.</name><affiliations><json:string>Laboratoire de Chimie Organique, Université Libre de Bruxelles (U.L.B.), Avenue F. D. Roosevelt 50, CP160/06, B‐1050 Brussels, Belgium, Fax: (+32) 2‐650‐27‐98</json:string><json:string>E-mail: ijabin@ulb.ac.be</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>calixarenes</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>host–guest systems</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>molecular platform</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>regioselectivity</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>supramolecular chemistry</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>synthetic methods</value></json:item></subject><articleId><json:string>CHEM200701770</json:string></articleId><language><json:string>eng</json:string></language><originalGenre><json:string>article</json:string></originalGenre><abstract>An elegant methodology based on the synergistic combination of coordination and host–guest chemistry led to the highly efficient synthesis of a unique C3v‐symmetrical, calix[6]arene‐based molecular platform with three protected amino arms in alternating positions. The key step involves the formation of a stable supramolecular host–guest ZnII complex from a C6v‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the ZnII ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the C3v‐symmetrical complex in such a way that the uncoordinated NH2 groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc2O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a C3v‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. 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The key step involves the formation of a stable supramolecular host–guest ZnII complex from a C6v‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the ZnII ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the C3v‐symmetrical complex in such a way that the uncoordinated NH2 groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc2O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a C3v‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. Examples of such readily available C3v‐symmetrical calixarene‐based building blocks are extremely rare in the literature.</p></abstract><abstract><p>Selective protection of a calix[6]arene on the narrow rim: Zn coordination of a calix[6]arene bearing six amino arms in the presence of a strong donor (L) and a polar neutral molecule (AcNH2) led to a stable C3v‐symmetrical host–guest Zn complex (see scheme). The remaining free amino arms in alternating positions can be selectively and quantitatively protected with Boc2O providing a unique example of a C3v‐symmetrical calix[6]arene‐based molecular platform that can be easily synthesised on a large scale.</p></abstract><textClass xml:lang="en"><keywords scheme="keyword"><list><head>keywords</head><item><term>calixarenes</term></item><item><term>host–guest systems</term></item><item><term>molecular platform</term></item><item><term>regioselectivity</term></item><item><term>supramolecular chemistry</term></item><item><term>synthetic methods</term></item></list></keywords></textClass><textClass><keywords scheme="Journal Subject"><list><head>article-category</head><item><term>Full Paper</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="2007-11-09">Received</change><change when="2008-04-07">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><original>false</original><mimetype>text/plain</mimetype><extension>txt</extension><uri>https://api.istex.fr/document/64C055A33BE39E38ADA811CB60C82A7EBAAEA847/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="Wiley, elements deleted: body"><istex:xmlDeclaration>version="1.0" encoding="UTF-8" standalone="yes"</istex:xmlDeclaration><istex:document><component version="2.0" type="serialArticle" xml:lang="en"><header><publicationMeta level="product"><publisherInfo><publisherName>WILEY‐VCH Verlag</publisherName><publisherLoc>Weinheim</publisherLoc></publisherInfo><doi registered="yes">10.1002/(ISSN)1521-3765</doi><issn type="print">0947-6539</issn><issn type="electronic">1521-3765</issn><idGroup><id type="product" value="CHEM"></id></idGroup><titleGroup><title type="main" xml:lang="en">Chemistry – A European Journal</title><title type="short">Chemistry – A European Journal</title></titleGroup></publicationMeta><publicationMeta level="part" position="110"><doi origin="wiley" registered="yes">10.1002/chem.v14:11</doi><numberingGroup><numbering type="journalVolume" number="14">14</numbering><numbering type="journalIssue">11</numbering></numberingGroup><coverDate startDate="2008-04-07">April 7, 2008</coverDate></publicationMeta><publicationMeta level="unit" type="article" position="12" status="forIssue"><doi origin="wiley" registered="yes">10.1002/chem.200701770</doi><idGroup><id type="unit" value="CHEM200701770"></id></idGroup><countGroup><count type="pageTotal" number="7"></count></countGroup><titleGroup><title type="articleCategory">Full Paper</title><title type="tocHeading1">Full Papers</title></titleGroup><copyright ownership="publisher">Copyright © 2008 WILEY‐VCH Verlag GmbH & Co. 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D. Roosevelt 50, CP160/06, B‐1050 Brussels, Belgium, Fax: (+32) 2‐650‐27‐98</unparsedAffiliation></affiliation><affiliation xml:id="ab" countryCode="FR" type="organization"><unparsedAffiliation>URCOM, Université du Havre, Faculté des Sciences et Techniques, 25 rue Philippe Lebon, BP 540, 76058 Le Havre cedex, France</unparsedAffiliation></affiliation><affiliation xml:id="ac" countryCode="FR" type="organization"><unparsedAffiliation>Institut Lavoisier, UMR CNRS 8180, Université de Versailles St‐Quentin en Yvelines, 45 av. des Etats‐Unis, 78035 Versailles cedex, France</unparsedAffiliation></affiliation></affiliationGroup><keywordGroup xml:lang="en" type="author"><keyword xml:id="kwd1">calixarenes</keyword><keyword xml:id="kwd2">host–guest systems</keyword><keyword xml:id="kwd3">molecular platform</keyword><keyword xml:id="kwd4">regioselectivity</keyword><keyword xml:id="kwd5">supramolecular chemistry</keyword><keyword xml:id="kwd6">synthetic methods</keyword></keywordGroup><fundingInfo><fundingAgency>the French Ministry of Research</fundingAgency></fundingInfo><supportingInformation><p>Supporting information for this article is available on the WWW under <url href="http://www.wiley-vch.de/contents/jc_2111/2008/f701770_s.pdf">http://www.wiley‐vch.de/contents/jc_2111/2008/f701770_s.pdf</url> or from the author.</p></supportingInformation><abstractGroup><abstract type="main" xml:lang="en"><title type="main">Abstract</title><p>An elegant methodology based on the synergistic combination of coordination and host–guest chemistry led to the highly efficient synthesis of a unique <i>C</i><sub>3<i>v</i></sub>‐symmetrical, calix[6]arene‐based molecular platform with three protected amino arms in alternating positions. The key step involves the formation of a stable supramolecular host–guest Zn<sup>II</sup> complex from a <i>C</i><sub>6<i>v</i></sub>‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the Zn<sup>II</sup> ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the <i>C</i><sub>3<i>v</i></sub>‐symmetrical complex in such a way that the uncoordinated NH<sub>2</sub> groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc<sub>2</sub>O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a <i>C</i><sub>3<i>v</i></sub>‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. Examples of such readily available <i>C</i><sub>3<i>v</i></sub>‐symmetrical calixarene‐based building blocks are extremely rare in the literature.</p></abstract><abstract type="graphical" xml:lang="en"><p><b>Selective protection of a calix[6]arene on the narrow rim</b>: Zn coordination of a calix[6]arene bearing six amino arms in the presence of a strong donor (L) and a polar neutral molecule (AcNH<sub>2</sub>) led to a stable <i>C</i><sub>3<i>v</i></sub>‐symmetrical host–guest Zn complex (see scheme). The remaining free amino arms in alternating positions can be selectively and quantitatively protected with Boc<sub>2</sub>O providing a unique example of a <i>C</i><sub>3<i>v</i></sub>‐symmetrical calix[6]arene‐based molecular platform that can be easily synthesised on a large scale.<blockFixed type="graphic"><mediaResourceGroup><mediaResource alt="image" eRights="yes" copyright="WILEY-VCH" href="urn:x-wiley:09476539:media:CHEM200701770:content"></mediaResource><mediaResource alt="thumbnail image" rendition="webLoRes" mimeType="image/gif" href=""></mediaResource><mediaResource alt="original image" rendition="webOriginal" mimeType="image/gif" href=""></mediaResource><mediaResource alt="magnified image" rendition="webHiRes" mimeType="image/gif" href=""></mediaResource></mediaResourceGroup></blockFixed></p></abstract></abstractGroup></contentMeta></header></component></istex:document></istex:metadataXml><mods version="3.6"><titleInfo lang="en"><title>Highly Selective Synthesis of a 1,3,5‐Tris‐Protected Calix[6]arene‐Type Molecular Platform through Coordination and Host–Guest Chemistry</title></titleInfo><titleInfo type="alternative" contentType="CDATA" lang="en"><title>Highly Selective Synthesis of a 1,3,5‐Tris‐Protected Calix[6]arene‐Type Molecular Platform through Coordination and Host–Guest Chemistry</title></titleInfo><name type="personal"><namePart type="given">Stéphane</namePart><namePart type="family">Le Gac</namePart><namePart type="termsOfAddress">Dr.</namePart><affiliation>URCOM, Université du Havre, Faculté des Sciences et Techniques, 25 rue Philippe Lebon, BP 540, 76058 Le Havre cedex, France</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Jérôme</namePart><namePart type="family">Marrot</namePart><namePart type="termsOfAddress">Dr.</namePart><affiliation>Institut Lavoisier, UMR CNRS 8180, Université de Versailles St‐Quentin en Yvelines, 45 av. des Etats‐Unis, 78035 Versailles cedex, France</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Ivan</namePart><namePart type="family">Jabin</namePart><namePart type="termsOfAddress">Prof.</namePart><affiliation>Laboratoire de Chimie Organique, Université Libre de Bruxelles (U.L.B.), Avenue F. D. Roosevelt 50, CP160/06, B‐1050 Brussels, Belgium, Fax: (+32) 2‐650‐27‐98</affiliation><affiliation>E-mail: ijabin@ulb.ac.be</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="article" displayLabel="article"></genre><originInfo><publisher>WILEY‐VCH Verlag</publisher><place><placeTerm type="text">Weinheim</placeTerm></place><dateIssued encoding="w3cdtf">2008-04-07</dateIssued><dateCaptured encoding="w3cdtf">2007-11-09</dateCaptured><copyrightDate encoding="w3cdtf">2008</copyrightDate></originInfo><language><languageTerm type="code" authority="rfc3066">en</languageTerm><languageTerm type="code" authority="iso639-2b">eng</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType><extent unit="figures">7</extent><extent unit="references">39</extent></physicalDescription><abstract lang="en">An elegant methodology based on the synergistic combination of coordination and host–guest chemistry led to the highly efficient synthesis of a unique C3v‐symmetrical, calix[6]arene‐based molecular platform with three protected amino arms in alternating positions. The key step involves the formation of a stable supramolecular host–guest ZnII complex from a C6v‐symmetrical calix[6]hexaamine. Indeed, in the presence of a polar neutral guest and a strong donor that acts as an exogenous ligand, three alternating amino groups of this calix[6]hexaamine are selectively coordinated to the ZnII ion while the three others remain free and are thus much more reactive toward chemical reagents. In addition to this protective role, the metal centre preorganises the C3v‐symmetrical complex in such a way that the uncoordinated NH2 groups are directed toward the outside of the cavity; they are then accessible for a chemical transformation. Hence, reaction of these alternating free amino groups with a protective reagent (i.e., Boc2O) followed by zinc decoordination quantitatively and selectively yielded the 1,3,5‐tris‐Boc‐protected calixarene derivative on a gram scale. It was shown that the presence of all the partners of the key intermediate Zn complex (i.e., the metal centre, the exogenous ligand and the included guest) is crucial for a high selectivity. Finally, a two step sequence that led to a C3v‐symmetrical 1,3,5‐tris‐acetylated calix[6]hexaamine through the removal of the Boc groups illustrates that the 1,3,5‐tris‐protected calix[6]hexaamine is a promising molecular platform. Examples of such readily available C3v‐symmetrical calixarene‐based building blocks are extremely rare in the literature.</abstract><abstract>Selective protection of a calix[6]arene on the narrow rim: Zn coordination of a calix[6]arene bearing six amino arms in the presence of a strong donor (L) and a polar neutral molecule (AcNH2) led to a stable C3v‐symmetrical host–guest Zn complex (see scheme). The remaining free amino arms in alternating positions can be selectively and quantitatively protected with Boc2O providing a unique example of a C3v‐symmetrical calix[6]arene‐based molecular platform that can be easily synthesised on a large scale.</abstract><note type="funding">the French Ministry of Research</note><subject lang="en"><genre>keywords</genre><topic>calixarenes</topic><topic>host–guest systems</topic><topic>molecular platform</topic><topic>regioselectivity</topic><topic>supramolecular chemistry</topic><topic>synthetic methods</topic></subject><relatedItem type="host"><titleInfo><title>Chemistry – A European Journal</title></titleInfo><titleInfo type="abbreviated"><title>Chemistry – A European Journal</title></titleInfo><genre type="journal">journal</genre><note type="content"> Supporting information for this article is available on the WWW under http://www.wiley‐vch.de/contents/jc_2111/2008/f701770_s.pdf or from the author.</note><subject><genre>article-category</genre><topic>Full Paper</topic></subject><identifier type="ISSN">0947-6539</identifier><identifier type="eISSN">1521-3765</identifier><identifier type="DOI">10.1002/(ISSN)1521-3765</identifier><identifier type="PublisherID">CHEM</identifier><part><date>2008</date><detail type="volume"><caption>vol.</caption><number>14</number></detail><detail type="issue"><caption>no.</caption><number>11</number></detail><extent unit="pages"><start>3316</start><end>3322</end><total>7</total></extent></part></relatedItem><identifier type="istex">64C055A33BE39E38ADA811CB60C82A7EBAAEA847</identifier><identifier type="DOI">10.1002/chem.200701770</identifier><identifier type="ArticleID">CHEM200701770</identifier><accessCondition type="use and reproduction" contentType="copyright">Copyright © 2008 WILEY‐VCH Verlag GmbH & Co. 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