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postgraduate thesis: Amine functionalized polymeric catalysts and reagents

TitleAmine functionalized polymeric catalysts and reagents
Authors
Issue Date2011
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Lu, J. [陆今妮]. (2011). Amine functionalized polymeric catalysts and reagents. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775252
AbstractPolymer-supported reagents and catalysts, which allow for simple product separation and easy recycling, have been widely studied in the context of organic synthesis. The past decade has witnessed a number of new variations of polymeric materials, and among the most frequently immobilized functionalities are amines that possess versatile synthetic utilities. Polymers with new structures and improved properties for use in synthesis have been continuously developed since the support may impact the chemical reactions in which they are used in various ways. A new heterogeneous polystyrene-based amine, rasta resin-DMAP, has been synthesized and used in addition reactions of carbon dioxide to epoxides to afford cyclic carbonate products. This new material was found to be a more efficient catalyst than divinylbenzene cross-linked polystyrene supported DMAP, and was readily recycled without significant loss of catalytic activity. Compared to polymers bearing a single functionality, polymers possessing multiple different functional groups attached to a single polymer backbone would have greater potential utility, especially in reactions requiring multiple catalysts or reagents. As an example of this concept, a bifunctional polystyrene bearing both DMAP and piperazine groups has been prepared and applied as an organocatalyst for decarboxylative Doebner-Knoevenagel reactions of arylaldehydes and mono-ethyl malonate to produce (E)-,-unsaturated esters in high yields. Additionally, both non-cross-linked and cross-linked bifunctional polystyrenes featuring amine and thiourea groups have been developed, and their catalytic performance were evaluated in reactions of nitroalkenes with either nitroalkanes or sulfur ylides. Both polymers proved to be efficient catalysts in these reactions and the insoluble polymer demonstrated high recyclability. Control experiments using monofunctional polymers indicated that both catalytic groups of these bifunctional polymers are essential and they could work cooperatively to achieve efficient catalysis. Finally, a second generation bifunctional phosphine-amine polymer, rasta resin-PPh3-NBniPr2, was prepared and examined in tandem Wittig-reductive aldol reactions. In these reaction cascades, the phosphine oxide groups generated from the Wittig reaction served as the catalyst for the reductive aldol reaction, and moderate yields of structurally diverse -hydroxy ketones could be obtained from one-pot processes involving 5 sequential reactions.
DegreeDoctor of Philosophy
SubjectAmines.
Polymers.
Catalysts.
Supported reagents.
Dept/ProgramChemistry
Persistent Identifierhttp://hdl.handle.net/10722/180062

 

DC FieldValueLanguage
dc.contributor.authorLu, Jinni.-
dc.contributor.author陆今妮.-
dc.date.accessioned2013-01-17T02:11:28Z-
dc.date.available2013-01-17T02:11:28Z-
dc.date.issued2011-
dc.identifier.citationLu, J. [陆今妮]. (2011). Amine functionalized polymeric catalysts and reagents. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775252-
dc.identifier.urihttp://hdl.handle.net/10722/180062-
dc.description.abstractPolymer-supported reagents and catalysts, which allow for simple product separation and easy recycling, have been widely studied in the context of organic synthesis. The past decade has witnessed a number of new variations of polymeric materials, and among the most frequently immobilized functionalities are amines that possess versatile synthetic utilities. Polymers with new structures and improved properties for use in synthesis have been continuously developed since the support may impact the chemical reactions in which they are used in various ways. A new heterogeneous polystyrene-based amine, rasta resin-DMAP, has been synthesized and used in addition reactions of carbon dioxide to epoxides to afford cyclic carbonate products. This new material was found to be a more efficient catalyst than divinylbenzene cross-linked polystyrene supported DMAP, and was readily recycled without significant loss of catalytic activity. Compared to polymers bearing a single functionality, polymers possessing multiple different functional groups attached to a single polymer backbone would have greater potential utility, especially in reactions requiring multiple catalysts or reagents. As an example of this concept, a bifunctional polystyrene bearing both DMAP and piperazine groups has been prepared and applied as an organocatalyst for decarboxylative Doebner-Knoevenagel reactions of arylaldehydes and mono-ethyl malonate to produce (E)-,-unsaturated esters in high yields. Additionally, both non-cross-linked and cross-linked bifunctional polystyrenes featuring amine and thiourea groups have been developed, and their catalytic performance were evaluated in reactions of nitroalkenes with either nitroalkanes or sulfur ylides. Both polymers proved to be efficient catalysts in these reactions and the insoluble polymer demonstrated high recyclability. Control experiments using monofunctional polymers indicated that both catalytic groups of these bifunctional polymers are essential and they could work cooperatively to achieve efficient catalysis. Finally, a second generation bifunctional phosphine-amine polymer, rasta resin-PPh3-NBniPr2, was prepared and examined in tandem Wittig-reductive aldol reactions. In these reaction cascades, the phosphine oxide groups generated from the Wittig reaction served as the catalyst for the reductive aldol reaction, and moderate yields of structurally diverse -hydroxy ketones could be obtained from one-pot processes involving 5 sequential reactions.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.source.urihttp://hub.hku.hk/bib/B4775252X-
dc.subject.lcshAmines.-
dc.subject.lcshPolymers.-
dc.subject.lcshCatalysts.-
dc.subject.lcshSupported reagents.-
dc.titleAmine functionalized polymeric catalysts and reagents-
dc.typePG_Thesis-
dc.identifier.hkulb4775252-
dc.description.thesisnameDoctor of Philosophy-
dc.description.thesislevelDoctoral-
dc.description.thesisdisciplineChemistry-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b4775252-
dc.date.hkucongregation2012-

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