Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
A Simple and Efficient Catalyst System for the Asymmetric Transfer Hydrogenation of Ketones
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
2007 (engelsk)Inngår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, nr 16, s. 2541-2544Artikkel i tidsskrift (Fagfellevurdert) Published
sted, utgiver, år, opplag, sider
2007. nr 16, s. 2541-2544
Emneord [en]
alcohols (benzene compounds);reduction, hydrogenation;diastereoselective syntheses, enantioselective syntheses (incl. cis/trans-isomerism)
HSV kategori
Identifikatorer
URN: urn:nbn:se:su:diva-24562DOI: 10.1002/chin.200808080ISI: 000250300100015OAI: oai:DiVA.org:su-24562DiVA, id: diva2:197803
Tilgjengelig fra: 2007-11-22 Laget: 2007-11-14 Sist oppdatert: 2017-12-13bibliografisk kontrollert
Inngår i avhandling
1. Transition Metal Hydrides: Biomimetic Studies and Catalytic Applications
Åpne denne publikasjonen i ny fane eller vindu >>Transition Metal Hydrides: Biomimetic Studies and Catalytic Applications
2007 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

In this thesis, studies of the nature of different transition metal-hydride complexes are described. The first part deals with the enantioswitchable behaviour of rhodium complexes derived from amino acids, applied in asymmetric transfer hydrogenation of ketones. We found that the use of amino acid thio amide ligands resulted in the formation of the R-configured product, whereas the use of the corresponding hydroxamic acid- or hydrazide ligands selectively gave the S-alcohol.

Structure/activity investigations revealed that the stereochemical outcome of the catalytic reaction depends on the ligand mode of coordination.

In the second part, an Fe hydrogenase active site model complex with a labile amine ligand has been synthesized and studied. The aim of this study was to find a complex that efficiently catalyzes the reduction of protons to molecular hydrogen under mild conditions. We found that the amine ligand functions as a mimic of the loosely bound ligand which is part of the active site in the hydrogenase.

Further, an Fe hydrogenase active site model complex has been coupled to a photosensitizer with the aim of achieving light induced hydrogen production. The redox properties of the produced complex are such that no electron transfer from the photosensitizer part to the Fe moiety occurs.

In the last part of this thesis, the development of a protocol for the transfer hydrogenation of ketones to secondary alcohols without the involvement of transition metal catalysts is described. A variety of ketones were efficiently reduced in 2-propanol using catalytic amounts of alkali alkoxide under microwave irradiation.

sted, utgiver, år, opplag, sider
Stockholm: Institutionen för organisk kemi, 2007
Emneord
transition metals, catalysis, bioinorganic chemistry, hydrides
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-7187 (URN)978-91-7155-539-7 (ISBN)
Disputas
2007-12-14, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2007-11-22 Laget: 2007-11-14 Sist oppdatert: 2015-10-18bibliografisk kontrollert
2. Asymmetric transfer hydrogenation of ketones: Catalyst development and mechanistic investigation
Åpne denne publikasjonen i ny fane eller vindu >>Asymmetric transfer hydrogenation of ketones: Catalyst development and mechanistic investigation
2011 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The development of ligands derived from natural amino acids for asymmetric transfer hydrogenation (ATH) of prochiral ketones is described herein. In the first part, reductions performed in alcoholic media are examined, where it is found that amino acid-derived hydroxamic acids and thioamides, respectively, are simple and versatile ligands that in combination with [RhCp*Cl2]2 efficiently catalyze this particular transformation. Selectivities up to 97% ee of the corresponding secondary alcohols are obtained, and it is furthermore observed that the two different ligand classes, albeit based on the same amino acid scaffold, give rise to products of opposite configuration.

The highly interesting enantioswitchable nature of the two abovementioned catalysts is studied in detail by mechanistic investigations. A structure/activity correlation analysis is performed, which reveals that the diverse behavior of the catalysts arise from different interactions between the ligands and the metal. Kinetic studies furthermore stress the catalyst divergence, since a difference in the rate determining step is established from initial rate measurements. In addition, rate constants are determined for each step of the overall reduction process.

In the last part, catalyst development for ATH executed in water is discussed. The applicability of hydroxamic acid ligands is further extended, and catalysts based on these compounds are found to be efficient and compatible with aqueous conditions. The structurally even simpler amino acid amide is also evaluated as a ligand, and selectivities up to 90% ee are obtained in the reduction of a number of aryl alkyl ketones. The very challenging reduction of dialkyl ketones is moreover examined in the Rh-catalyzed aqueous ATH, where a modified surfactant-resembling sulfonylated diamine is used as ligand, and the reaction is carried out in the presence of SDS-micelles. A positive effect is to some extent found on the catalyst performance upon addition of phase-transfer components, especially regarding the catalytic activity in the reduction of more hydrophobic substrates.

sted, utgiver, år, opplag, sider
Stockholm: Department of Organic Chemistry, Stockholm University, 2011. s. 49
Emneord
Asymmetric catalysis, reduction, amino acid, rhodium, mechanistic investigation, kinetic study
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-55412 (URN)978-91-7447-234-9 (ISBN)
Disputas
2011-04-29, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: In press.Tilgjengelig fra: 2011-04-07 Laget: 2011-03-14 Sist oppdatert: 2011-05-25bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekst

Søk i DiVA

Av forfatter/redaktør
Ahlford, KatrinAdolfsson, Hans
Av organisasjonen
I samme tidsskrift
Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry

Søk utenfor DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric

doi
urn-nbn
Totalt: 749 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf