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Palladium-Catalyzed Electrophilic Substitution via Monoallylpalladium Intermediates
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.ORCID-id: 0000-0002-9349-7137
2003 (Engelska)Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 42, nr 31, s. 3656-3658Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
2003. Vol. 42, nr 31, s. 3656-3658
Nyckelord [en]
aldehydes, allylation, electrophilic substitution, homogenous catalysis, palladium
Identifikatorer
URN: urn:nbn:se:su:diva-22714DOI: 10.1002/anie.200351477OAI: oai:DiVA.org:su-22714DiVA, id: diva2:189307
Anmärkning
Part of urn:nbn:se:su:diva-105Tillgänglig från: 2004-04-22 Skapad: 2004-04-22 Senast uppdaterad: 2019-12-16Bibliografiskt granskad
Ingår i avhandling
1. Development of Palladium-Catalyzed Transformations Involving η1-Allypalladium Species
Öppna denna publikation i ny flik eller fönster >>Development of Palladium-Catalyzed Transformations Involving η1-Allypalladium Species
2004 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis is focused on investigation of the structure, reactivity and isomerization reactions of η1-allylpalladium complexes, which are key intermediates in catalytic transformations. The first part of this thesis concerns the structure and reactivity of bis-allylpalladium complexes. We have studied the regioselective palladium-catalyzed coupling reaction of various dialkylsubstituted allyl chlorides with allylstannanes and benzylidenemalonitrile, affording functionalized 1,7-octadienes. We have also found that benzylidenemalonitrile can be replaced by isocyanates providing bis-allylated amides. The second part is a computational study on the η3-η1-η3 isomerization of allylpalladium complexes. The mechanism of the isomerization was studied by DFT. It was found that the isomerization involves tetra-coordinated η1-allylpalladium intermediates. Alkyl substitution of the metalated carbon leads to destabilization of the η1-allylpalladium intermediate, which increases the activation energy of the isomerization process. The last part describes our efforts to extend the synthetic scope of mono-allylpalladium chemistry to include catalytic allylation of imine and aldehyde substrates. We have found that this reactivity can be achieved by the use of strongly coordinating tridentate ligands on palladium. The η1-allylpalladium intermediate has been observed by NMR-spectroscopy, and DFT calculations have been performed to show the feasibility of an electrophilic attack occuring on the allyl moiety.

Ort, förlag, år, upplaga, sidor
Stockholm: Institutionen för organisk kemi, 2004. s. 65
Nyckelord
Palladium, Homogenous catalysis, Allylation, Electrophilic substitution, Density functional calculations
Nationell ämneskategori
Organisk kemi
Identifikatorer
urn:nbn:se:su:diva-105 (URN)91-7265-868-1 (ISBN)
Disputation
2004-05-14, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2004-04-22 Skapad: 2004-04-22 Senast uppdaterad: 2010-02-11Bibliografiskt granskad
2. Employment of Palladium Pincer Complex Catalysts and Lewis Acids for Synthesis and Transformation of Organometallic Compounds
Öppna denna publikation i ny flik eller fönster >>Employment of Palladium Pincer Complex Catalysts and Lewis Acids for Synthesis and Transformation of Organometallic Compounds
2005 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis is mainly focused on the development of new palladium catalyzed transformations using so-called “pincer” complexes. These complexes were applied as catalysts in two important areas of organometallic chemistry: substitution of propargylic substrates by dimetallic reagents; and allylation of aldehydes and imines by allylstannanes. In addition, this thesis includes studies on Lewis acid mediated cyclization reactions of allylsilanes with aldehydes.

Pincer complex catalyzed substitution of various propargylic substrates could be achieved under mild conditions using tin and silicon based dimetallic reagents to obtain propargyl- and allenylstannanes and silanes. The regioselectivity of the substitution reaction strongly depends on the steric and electronic effects of the propargylic substrate. According to our mechanistic studies the key intermediate of the reaction is an organostannane (or silane) coordinated pincer complex. DFT modeling studies on the transfer of the trimethylstannyl functionality to the propargylic substrate revealed a novel mechanism, which is based on the unique topology of the pincer-complex catalysts.

Our further studies showed that palladium pincer complexes can be employed as efficient catalysts for electrophilic allylic substitution of allylstannanes with aldehyde and imine substrates. In contrast to previous applications for electrophilic allylic substitutions via bis-allylpalladium complexes, this reaction involves mono-allylpalladium intermediates which were observed by 1H-NMR spectroscopy.

The last chapter of this thesis is focused on Lewis-acid mediated cyclization of hydroxy functionalized allylsilanes, which afford tetrahydropyran derivatives with a high stereoselectivity.

Ort, förlag, år, upplaga, sidor
Stockholm: Institutionen för organisk kemi, 2005. s. 58
Nationell ämneskategori
Kemi
Identifikatorer
urn:nbn:se:su:diva-416 (URN)91-7155-026-7 (ISBN)
Disputation
2005-04-29, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2005-03-24 Skapad: 2005-03-24 Senast uppdaterad: 2010-02-11Bibliografiskt granskad

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Szabó, Kálmán J.
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