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- Kaukoranta, Päivi, et al.
(författare)
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Microwave-Assisted Asymmetric Intermolecular Heck Reaction using Phosphine-Thiazole Ligands
- 2007
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 349:7-18, s. 2595-2602
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Tidskriftsartikel (refereegranskat)abstract
- A series of new phosphine-thiazole compounds has been synthesized and used as efficient ligands in the palladium-catalyzed asymmetric intermolecular Heck coupling of 2,3-dihydrofuran with aryl triflates and cyclohexenyl triflate. Microwave heating was used to accelerate the reactions and gave complete conversions in as little as one hour. Products were obtained with good to excellent enantioselectivities.
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- Källström, Klas, et al.
(författare)
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Asymmetric hydrogenation of tri-substituted alkenes with Ir-NHC-thiazole complexes
- 2006
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Ingår i: Tetrahedron Letters. - : Elsevier BV. - 0040-4039 .- 1359-8562. ; 47:42, s. 7477-7480
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Tidskriftsartikel (refereegranskat)abstract
- An efficient chiral N-heterocyclic carbene ligand for the Ir-catalyzed asymmetric hydrogenation of largely unfunctionalized tri-substituted olefins has been developed. The Ir-NHC-thiazole catalyst is able to reduce a large variety of substrates with excellent conversions and good enantioselectivities with ee's ranging from 34% to 90%, depending on the geometry around the double bond of the substrates.
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- Källström, Klas, 1976-
(författare)
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Catalytic Asymmetric Ketone and Alkene Reductions Using Transition Metal Complexes
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contains seven papers dealing with iridium and ruthenium based catalytic asymmetric reductions, either of ketones into chiral alcohols, or olefins into chiral alkanes. The first part of the thesis describes how we have designed and evaluated new bicyclic ligands containing either N,S or N,N chelating atoms. The ligands have been evaluated in the asymmetric Ir-catalyzed transfer hydrogenation of acetophenone. The complexes evaluated induced good enentioselectivity of the product. Moreover we have also utilized a commercially available chiral diamine (QCD-amine) as a ligand in the Ru-catalyzed hydrogenation of prochiral ketones, with excellent enantioselectivity for some of the substrates used. As part of this work we investigated, both theoretically and experimentally, the mechanism of this hydrogenation. Based on these results we have proposed a new reaction mechanism for this type of hydrogenations which involves active participation of the solvent in the catalytic cycle. The last part of the thesis describes the design, synthesis and evaluation of N,P and N2C-carbene,N ligands for the Ir-catalyzed hydrogenation of carbon-carbon double bonds. The selectivities obtained in these investigations are among the best reported so far for a broad variation of substrates. A selectivity model for this hydrogenation has been derived and used in the rationalization of the results. As a part of this work we have synthesized and evaluated a new class of substrates, vinyl silanes, and showed that the scope of the hydrogenation reaction can be expanded to this new substrate class.
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- Mume, Eskender, et al.
(författare)
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Exploring the substrate scope of the Ru(II)-catalyzed kharasch reaction
- 2007
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Ingår i: Collection of Czechoslovak Chemical Communications. - : Institute of Organic Chemistry & Biochemistry. - 0010-0765 .- 1212-6950. ; 72:8, s. 1005-1013
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Tidskriftsartikel (refereegranskat)abstract
- The Kharasch reaction, or atom-transfer addition of polyhalogenated alkanes to alkenes is known to be catalyzed by a number of Ru( II) complexes. The easily prepared [ RuCl2( PPh3)(3)] was used to investigate the reaction scope. A number of halogenated alkanes were added to a range of alkenes with good to excellent regioselectivities.
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- Paptchikhine, Alexander, et al.
(författare)
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New ligands for the RuCp*-diamine catalysed asymmetric hydrogenation of aryl ketones
- 2007
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Ingår i: Comptes rendus. Chimie. - : Elsevier BV. - 1631-0748 .- 1878-1543. ; 10:3, s. 213-219
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Tidskriftsartikel (refereegranskat)abstract
- New chiral diamine ligands have been synthesized and evaluated in the asymmetric Ru-catalyzed hydrogenation of prochiral aryl ketones. All catalysts showed good conversions with observed enantioselectivities ranging from moderate to good.
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