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  • 1.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Alkene and Imino Reductions by Organocatalysis2008Ingår i: Modern Reduction Methods, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim , 2008, s. 341-361Kapitel i bok, del av antologi (Refereegranskat)
  • 2.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Product Class 2: Epoxides (Oxiranes): Synthesis from Alkenes by Metal-Mediated Oxidation2008Ingår i: Houben-Weyl Methods of Molecular Transformations: Compounds with One Saturated Carbon-Heteroatom Bond, Georg Thieme Verlag KG, Stuttgart , 2008, s. 227-276Kapitel i bok, del av antologi (Refereegranskat)
  • 3.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Transition metal-catalyzed epoxidation of alkenes2010Ingår i: Modern Oxidation Methods / [ed] Jan-Erling Bäckvall, Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010, 2, s. 37-84Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 4.
    Adrian Meredith, Jenny
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Björklund, Catarina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Edlund, Michael
    Jansson, Katarina
    Lindberg, Jimmy
    Vrang, Lotta
    Hallberg, Anders
    Institutionen för läkemedelskemi, Uppsala universitet.
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Design and Synthesis of BACE-1 Inhibitors Containing a New Hydroxyethylene (HE) Scaffold: Potent activities in a cellular assayManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In a preceding report from our group we disclosed the development of a novel HE transition state isostere with a difluorophenoxymethyl side chain in the P1 position and a methoxy group in the P1’ position furnishing highly potent inhibitors of BACE-1 (i.e. lead compound 1), which moreover exhibit very promising selectivity over cathepsin D. In a continuation of this work with the aim at improving on the cell-based activity and pharmacokinetic properties, we have further developed the SAR for the P1 side chain of inhibitor 1 whereby the P1 side chain oxygen has been substituted for an amine, a carbon or a bond. The chemistry developed for the previous HE inhibitor structure 1 has now been extended to readily accommodate the introduction of new P1 side chains into this new HE scaffold. These modifications have given rise to several highly potent inhibitors where the most potent displayed a BACE-1 Ki value of 0.2 nM and a cell-based Aβ40 IC50 value of 9 nM. Thus, regarding the enzyme inhibition in the cell assay a more than 600-fold improvement compared to compound 1 was achieved via minor structural alterations.

  • 5.
    Adrian Meredith, Jenny
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Björklund, Catarina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jansson, Katarina
    Hallberg, Anders
    Institutionen för läkemedelskemi, Uppsala universitet.
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    P2’-truncated BACE-1 inhibitors with a novel hydroxethylene-like core2010Ingår i: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 45, nr 2, s. 542-554Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Highly potent BACE-1 protease inhibitors derived from a novel hydroxyethylene-like core structure were recently developed by our group using X-ray crystal structure data and molecular modelling. In a continuation of this work guided by molecular modelling we have explored a truncated core motif where the P2’ amide group is replaced by an ether linkage resulting in a set of alkoxy, aryloxy and alkylaryl groups, with the overall aim to reduce molecular weight and the number of amide bonds to increase permeability and bestow the inhibitors with drug-like features. The most potent of these inhibitors displayed a BACE-1 IC50 value of 140 nM. The synthesis of these BACE-1 inhibitors utilizes readily available starting materials, furnishing the target compounds in good overall yields.

  • 6.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Amino acid-derived amides and hydroxamic acids as ligands for asymmetric transfer hydrogenation in aqueous media2011Ingår i: Catalysis communications, ISSN 1566-7367, E-ISSN 1873-3905, Vol. 12, nr 12, s. 1118-1121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amides and hydroxamic acids derived from α-amino acids were evaluated as ligands in combination with rhodium and iridium half-sandwich complexes in asymmetric transfer hydrogenation (ATH) of ketones. The reactions were performed in aqueous media using lithium formate as hydride source. The catalyst systems turned out to be highly efficient and ees up to 90% were obtained.

  • 7.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Amino Acid Derived Rhodium Complexes: On the Origin of Enantioselectivity and Enantioswitchability2009Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, nr 42, s. 11197-11209Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amino acid based thioamides, hydroxamic acids, and hydrazides have been evaluated as ligands in the rhodium-catalyzed asymmetric transfer hydrogenation of ketones in 2-propanol. Catalysts containing thioamide ligands derived from L-valine were found to selectively generate the product with an R configuration (95 % ee), whereas the corresponding L-valine-based hydroxamic acids or hydrazides facilitated the formation of the (S)-alcohols (97 and 91 % ee, respectively). The catalytic reduction was examined by performing a structure–activity correlation investigation with differently functionalized or substituted ligands and the results obtained indicate that the major difference between the thioamide and hydroxamic acid based catalysts is the coordination mode of the ligands. Kinetic experiments were performed and the rate constants for the reduction reactions were determined by using rhodium–arene catalysts derived from amino acid thioamide and hydroxamic acid ligands. The data obtained show that the thioamide-based catalyst systems demonstrate a pseudo-first-order dependence on the substrate, whereas pseudo-zero-order dependence was observed for the hydroxamic acid containing catalysts. Furthermore, the kinetic experiments revealed that the rate-limiting steps of the two catalytic systems differ. From the data obtained in the structure–activity correlation investigation and along with the kinetic investigation it was concluded that the enantioswitchable nature of the catalysts studied originates from different ligand coordination, which affects the rate-limiting step of the catalytic reduction reaction.

  • 8.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric transfer hydrogenation of ketones catalyzed by amino acid derived rhodium complexes: on the origin of enantioselectivity and enantioswitchability: Corrigendum to vol 15(2009) 42, pp. 11197-2010Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, nr 35, s. 10610-10610Artikel i tidskrift (Refereegranskat)
  • 9.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lind, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Mäler, Lena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rhodium-catalyzed asymmetric transfer hydrogenation of alkyl and aryl ketones in aqueous media2008Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 10, nr 8, s. 832-835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel lipophilic rhodium catalyst was evaluated in the enantioselective transfer hydrogenation of ketones in water using sodium formate as the hydride donor, and in the presence of sodium docecylsulfonate. Alkyl alkyl ketones were reduced in good yields and in moderate to good enantioselectivities, and the reduction of aryl alkyl ketones proceeded with excellent enantioselectivity (up to 97% ee).

  • 10.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Livendahl, Madeleine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Fine-tuning catalytic activity and selectivity-[Rh(amino acid thioamide)] complexes for efficient ketone reduction2009Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, nr 46, s. 6321-6324Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amino acid-derived thioamides are prepared and evaluated as ligands in the rhodium-catalyzed asymmetric transfer hydrogenation of ketones in 2-propanol. It is found that increasing the steric bulk at the C-terminus of the ligand had a positive impact on both activity and selectivity in the reduction reaction. In order to find the optimum catalyst, a study is performed on a series of thioamide ligands having substituents of varying size.

  • 11.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nordin, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mechanistic investigation of enantioswitchable catalysts for asymmetric transfer hydrogenation2010Ingår i: Abstracts of Papers, 239th ACS National Meeting, San Francisco , CA, United States, March 21-25, 2010, Washington: American Chemical Society , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 12.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Simple and Efficient Catalyst System for the Asymmetric Transfer Hydrogenation of Ketones2007Ingår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, nr 16, s. 2541-2544Artikel i tidskrift (Refereegranskat)
  • 13.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Chiral quinuclidine-based amine catalysts for the asymmetric one-pot, three-component aza-Baylis–Hillman reaction2003Ingår i: Tetrahedron Letters, Vol. 44, nr 12, s. 2521-2524Artikel i tidskrift (Refereegranskat)
  • 14.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Efficient microwave-assisted formation of functionalized 2,5-dihydropyrroles using ruthenium-catalyzed ring-closing metathesis2004Ingår i: Tetrahedron Letters, Vol. 45, nr 15, s. 3089-3092Artikel i tidskrift (Refereegranskat)
  • 15.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Selective formation of α-methylene-β-amino acid derivatives through the aza version of the baylis-Hillman reaction2001Ingår i: The Journal of Organic Chemistry, Vol. 66, s. 6498-6501Artikel i tidskrift (Refereegranskat)
  • 16.
    Balan, Daniela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Titanium isopropoxide as Efficient Catalyst for the aza-Baylis-Hillman reaction. Selective formation of α-methylene-β-amino acid derivatives2002Ingår i: The Journal of Organic Chemistry, Vol. 67, s. 2329-2334Artikel i tidskrift (Refereegranskat)
  • 17.
    Björklund, Catarina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jansson, Katarina
    Lindberg, Jimmy
    Vrang, Lotta
    Hallberg, Anders
    Rosenquist, Åsa
    Samuelsson, Bertil
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Discovery of Potent BACE-1 Inhibitors Containing a New Hydroxyethylene (HE) Scaffold: Exploration of P1’ Alkoxy Residues and an Aminoethylene (AE) Central Core2010Ingår i: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 18, nr 4, s. 1711-1723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In a preceding study we have described the development of a new hydroxyethylene (HE) core motif displaying P1 aryloxymethyl and P1’ methoxy substituents delivering potent BACE-1 inhibitors. In a continuation of this work we have now explored the SAR of the S1’ pocket by introducing a set of P1’ alkoxy groups and evaluated them as BACE-1 inhibitors. Previously the P1 and P1’ positions of the classical HE template have been relatively little explored due to the complexity of the chemical routes involved in modifications at these positions. However, the chemistries developed for the current HE template renders substituents in both the P1 and P1’ positions readily available for SAR exploration. The BACE-1 inhibitors prepared displayed IC50 values in the range of 4-45 nM, where the most potent compounds featured small P1’ groups. The cathepsin D selectivity which was high for the smallest P1’ sustituents (P1’=ethoxy, fold selectively >600) dropped for larger groups (P1’=benzyloxy, fold selectivity of 1.6). We have also confirmed the importance of both the hydroxyl group and its stereochemistry preference for this HE transition state isostere by preparing both the deoxygenated analogue and by inverting the configuration of the hydroxyl group to the R-configuration, which as expected resulted in large activity drops. Finally substituting the hydroxyl group by an amino group having the same configuration (S), which previously have been described to deliver potent BACE-1 inhibitors with advantageous properties, surprisingly resulted in a large drop in the inhibitory activity.

  • 18.
    Buitrago, Elina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    High Throughput Screening of a Catalyst Library for the Asymmetric Transfer Hydrogenation of Heteroaromatic Ketones: Formal Syntheses of (R)-Fluoxetine and (S)-Duloxetine2012Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 4, nr 12, s. 2082-2089Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A total of 21 amino acid based ligands including hydroxy amide, thioamide, and hydroxamic acid functionalities, respectively, were combined with [Ru(p-cymene)Cl2]2 and [RhCp*Cl2]2, and used as catalysts for the asymmetric transfer hydrogenation of four different heteroaromatic ketones in 2-propanol. The reactions were performed on a Chemspeed automated high-throughput screening robotic platform. Optimal catalysts were identified for the individual heterocyclic substrate classes. Based on these results, the formal syntheses of the antidepressant drugs (R)-fluoxetine and (S)-duloxetine were conducted by using the found catalysts in the key reaction step, which results in high isolated yields (94?%) and excellent product enantioselectivities (>99?% ee) of the formed 1,3-amino alcohols.

  • 19.
    Buitrago, Elina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ryberg, Per
    Aztra Zeneca, Global Process R&D, Södertälje, Sweden.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selective reduction of heteroaromatic ketones: A combinatorial approach2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The enantioselective reduction of prochiral ketones is a most productiveway towards enantio enriched secondary alcohols used in the preparation of biologically active compounds. There are numerous transition metal catalyzed methods for this transformation, particularly based on Ru(II)-and Rh(I)-complexes, but there is a demand for a larger substrate scope. Heteroaromatic ketones are traditionally more challenging substrates. Normally a catalyst is developed for one benchmark substrate, and asubstrate screen is made with the best performing catalyst. Using this methodology, there is a high probability that for different substrates, another catalyst could outperform the one used. We have executed a multiple screen, containing a variety of different ligands together with both Ru and Rh, and heteroaromatic ketones to fine-tune, and find the optimum catalyst depending on the substrate. The acquired information was used to synthesize known, biologically active compounds, where the key reduction steps were performed with high enantioselectivities and yields.

  • 20.
    Buitrago, Elina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient and Selective Hydrosilylation of Carbonyls Catalyzed by Iron Acetate and N-Hydroxyethylimidazolium Salts2012Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, nr 1, s. 217-222Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aromatic aldehydes, along with aryl alkyl, heteroaryl alkyl, and dialkyl ketones were efficiently reduced to their corresponding primary and secondary alcohols, respectively, in high yields, using the commercially available and inexpensive polymeric silane, polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by in situ generated iron complexes containing hydroxyethyl-functionalized NHC ligands. Turnover frequencies up to 600 h−1 were obtained

  • 21.
    Buitrago, Elina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zani, Lorenzo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Fe/NHC-catalyzed hydrosilylation of aromatic ketones2009Ingår i: Abstracts of Papers, 238th ACS National Meeting, Washington, DC, United States, August 16-20, 2009, Washington, DC: American Chemical Society , 2009Konferensbidrag (Övrigt vetenskapligt)
  • 22.
    Buitrago, Elina
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zani, Lorenzo
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selective hydrosilylation of ketones catalyzed by in situ-generated iron NHC complexes2011Ingår i: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 25, nr 10, s. 748-752Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aryl alkyl-, heteroaryl alkyl- and dialkyl ketones were readily reduced to their corresponding secondary alcohols in high yields, using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by an in situ-generated iron complex, conveniently generated from iron(II) acetate and the commercially available N-heterocyclic carbene (NHC) precursor IPr·HCl.

  • 23. Coll, Mercedes
    et al.
    Ahlford, Katrin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pamies, Oscar
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dieguez, Montserrat
    Modular Furanoside Pseudodipeptides and Thioamides, Readily Available Ligand Libraries for Metal-Catalyzed Transfer Hydrogenation Reactions: Scope and Limitations2012Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, nr 2-3, s. 415-427Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two new highly modular carbohydrate-based, pseudodipeptide and thioamide ligand libraries have been synthesized for the rhodium- and ruthenium-catalyzed asymmetric transfer hydrogenation (ATH) of prochiral ketones. These series of ligands can be prepared efficiently from easily accessible D-xylose and D-glucose. The ligand libraries contain two main ligand structures (pseudodipeptide and thioamide) that have been designed by making systematic modifications to one of the most successful ligand families developed for the ATH. As well as studying the effect of these two ligand structures on the catalytic performance, we also evaluated the effect of modifying several of the ligand parameters. We found that the effectiveness of the ligands at transferring the chiral information in the product can be tuned by correctly choosing the ligand components (ligand structure and ligand parameters). Excellent enantioselectivities (ees up to 99%) were therefore obtained in both enantiomers of the alcohol products using a wide range of substrates.

  • 24. Coll, Mercedes
    et al.
    Pamies, Oscar
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dieguez, Montserrat
    Second-Generation Amino Acid Furanoside Based Ligands from D-Glucose for the Asymmetric Transfer Hydrogenation of Ketones2013Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, nr 12, s. 3821-3828Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel series of modular amino acid thioamide ligands functionalized with carbohydrates were introduced and employed in the rhodium-catalyzed asymmetric transfer hydrogenation (ATH) of aryl alkyl ketones, including the less-studied heteroaromatic ketones. The ligands are based on amino acid hydroxyamides (pseudodipeptides), which are the most successful ligands previously used in asymmetric hydrogen transfer reactions. High enantioselectivities [up to 99% enantiomeric excess (ee)] were achieved in the ATH of a wide range of aryl alkyl ketones by using catalysts generated insitu from [RhCl2Cp*](2) (Cp*=C5Me5) and thioamide ligands comprising a 3-benzyl glucofuranoside backbone and a bulky isopropyl group in the -amino acid moiety. Interestingly, both enantiomers of the alcohol products can readily be obtained with high enantioselectivity by simply changing the absolute configuration of the -amino acid. The good performance can be extended to a very challenging class of industrially interesting heteroaromatic ketones (up to 99%ee).

  • 25. Coll, Mercedes
    et al.
    Pàmies, Oscar
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diéguez, Montserrat
    Carbohydrate-based pseudo-dipeptides: new ligands for the highly enantioselective Ru-catalyzed transfer hydrogenation reaction2011Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, nr 44, s. 12188-12190Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ruthenium-complexes of novel carbohydrate based pseudo-dipeptide ligands effectively and selectively catalyze the reduction of a broad range of aryl–alkyl ketones under ATH conditions. Excellent enantioselectivities (>99% ee) are obtained using aminosugars as the sole source of chirality.

  • 26.
    Ekström, Jesper
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wettergren, Jenny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Simple and Efficient Catalytic Method for the Reduction of Ketones2007Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, nr 10, s. 1609-1613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A range of ketones was efficiently reduced in the presence of catalytic amounts of lithium isopropoxide in 2-propanol under microwave heating, with alcohol products being formed in yields up to 99 %.

  • 27.
    Kovalenko, Oleksandr O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly Efficient and Chemoselective Zinc-Catalyzed Hydrosilylation of Esters under Mild Conditions2015Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, nr 7, s. 2785-2788Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A mild and highly efficient catalytic hydrosilylation protocol for room-temperature ester reductions has been developed using diethylzinc as the catalyst. The methodology is operationally simple, displays high functional group tolerance and provides for a facile access to a broad range of different alcohols in excellent yields.

  • 28.
    Kovalenko, Oleksandr O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Huebner, Dennis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tandem alpha-Alkylation/Asymmetric Transfer Hydrogenation of Acetophenones with Primary Alcohols2014Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 30, s. 6639-6642Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A tandem -alkylation/asymmetric transfer hydrogenation of acetophenones with primary alcohols, mediated by a single ruthenium catalyst, is described. Under optimized reaction conditions and with use of [Ru(p-cymene)Cl-2](2) in combination with an amino acid hydroxyamide ligand, the chiral secondary alcohol products were isolated in moderate yields and in moderate to good enantiomeric excess (up to 89% ee).

  • 29.
    Kovalenko, Oleksandr O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Volkov, Alexey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mild and Selective Et2Zn-Catalyzed Reduction of Tertiary Amides under Hydrosilylation Conditions2015Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, nr 3, s. 446-449Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Diethylzinc (Et2Zn) can be used as an efficient and chemoselective catalyst for the reduction of tertiary amides under mild reaction conditions employing cost-effective polymeric silane (PMHS) as the hydride source. Crucial for the catalytic activity was the addition of a substoichiometric amount of lithium chloride to the reaction mixture. A series of amides containing different additional functional groups were reduced to their corresponding amines, and the products were isolated in good-to-excellent yields.

  • 30.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic α-Alkylation/Reduction of Ketones with Primary Alcohols To Furnish Secondary Alcohols2016Ingår i: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 48, nr 5, s. 644-652Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The formation of secondary alcohol products via a tandem -alkylation/transfer hydrogenation of ketones with primary alcohols is a little explored reaction with unrealized potential for green synthesis. This review covers the current literature in the field, including asymmetric versions of the reaction, and outlines future possibilities and challenges for the methodology. 1 Introduction 2 Formation of Racemic Alcohols 3 Formation of Enantiomerically Enriched Alcohols 4 Conclusions

  • 31.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-catalyzed asymmetric transfer hydrogenation of ketones in ethanol2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A ruthenium catalyst formed in situ by combining [Ru(p-cymene)Cl2]2 and an amino acid hydroxy-amide was found to catalyze efficiently the asymmetric reduction of aryl alkyl ketones under transfer hydrogenation conditions using ethanol as the hydrogen donor. The secondary alcohol products were obtained in moderate to good yields and with good to excellent enantioselectivity (up to 97% ee).

  • 32.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-catalyzed asymmetric transfer hydrogenation of ketones in ethanol2011Ingår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, nr 21, s. 2754-2758Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A ruthenium catalyst formed in situ by combining [Ru(p-cymene)Cl2]2 and an amino acid hydroxy-amide was found to catalyze efficiently the asymmetric reduction of aryl alkyl ketones under transfer hydrogenation conditions using ethanol as the hydrogen donor. The secondary alcohol products were obtained in moderate to good yields and with good to excellent enantioselectivity (up to 97% ee).

  • 33.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Direct Amide Coupling of Non-activated Carboxylic Acids and Amines Catalysed by Zirconium(IV) Chloride2012Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 13, s. 3822-3826Artikel i tidskrift (Refereegranskat)
  • 34.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Titanium(IV) Isopropoxide as an Efficient Catalyst for Direct Amidation of Nonactivated Carboxylic Acids2012Ingår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 23, nr 15, s. 2201-2204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Secondary and tertiary amides are formed in high yields, in an efficient and environmentally benign titanium(IV) isopropoxide catalyzed direct amidation of carboxylic acids with primary and secondary amines.

  • 35.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selander, Nicklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic amide formation from non-activated carboxylic acids and amines2014Ingår i: Chemical Society Reviews, ISSN 0306-0012, E-ISSN 1460-4744, Vol. 43, nr 8, s. 2714-2742Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The amide functionality is found in a wide variety of biological and synthetic structures such as proteins, polymers, pesticides and pharmaceuticals. Due to the fact that synthetic amides are still mainly produced by the aid of coupling reagents with poor atom-economy, the direct catalytic formation of amides from carboxylic acids and amines has become a field of emerging importance. A general, efficient and selective catalytic method for this transformation would meet well with the increasing demands for green chemistry procedures. This review covers catalytic and synthetically relevant methods for direct condensation of carboxylic acids and amines. A comprehensive overview of homogeneous and heterogeneous catalytic methods is presented, covering biocatalysts, Lewis acid catalysts based on boron and metals as well an assortment of other types of catalysts.

  • 36.
    Lundberg, Helena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhang, Jiji
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Algarra, Andrés G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Universidad de Cádiz, Spain.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Umeå University, Sweden.
    Mechanistic Elucidation of Zirconium-Catalyzed Direct Amidation2017Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, nr 6, s. 2286-2295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanism of the zirconium-catalyzed condensation of carboxylic acids and amines for direct formation of amides was studied using kinetics, NMR spectroscopy, and DFT calculations. The reaction is found to be first order with respect to the catalyst and has a positive rate dependence on amine concentration. A negative rate dependence on carboxylic acid concentration is observed along with S-shaped kinetic profiles under certain conditions, which is consistent with the formation of reversible off-cycle species. Kinetic experiments using reaction progress kinetic analysis protocols demonstrate that inhibition of the catalyst by the amide product can be avoided using a high amine concentration. These insights led to the design of a reaction protocol with improved yields and a decrease in catalyst loading. NMR spectroscopy provides important details of the nature of the zirconium catalyst and serves as the starting point for a theoretical study of the catalytic cycle using DFT calculations. These studies indicate that a dinuclear zirconium species can catalyze the reaction with feasible energy barriers. The amine is proposed to perform a nucleophilic attack at a terminal eta(2)-carboxylate ligand of the zirconium catalyst, followed by a C-O bond cleavage step, with an intermediate proton transfer from nitrogen to oxygen facilitated by an additional equivalent of amine. In addition, the DFT calculations reproduce experimentally observed effects on reaction rate, induced by electronically different substituents on the carboxylic acid.

  • 37. Margalef, Jèssica
    et al.
    Slagbrand, Tove
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Umeå University, Sweden.
    Diéguez, Montserrat
    Pàmies, Oscar
    Third-Generation Amino Acid Furanoside-Based Ligands from d-Mannose for the Asymmetric Transfer Hydrogenation of Ketones: Catalysts with an Exceptionally Wide Substrate Scope2016Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 358, nr 24, s. 4006-4018Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A modular ligand library of -amino acid hydroxyamides and thioamides was prepared from 10 different N-tert-butyloxycarbonyl-protected -amino acids and three different amino alcohols derived from 2,3-O-isopropylidene--d-mannofuranoside. The ligand library was evaluated in the half-sandwich ruthenium- and rhodium-catalyzed asymmetric transfer hydrogenation of a wide array of ketone substrates, including simple as well as sterically demanding aryl alkyl ketones, aryl fluoroalkyl ketones, heteroaromatic alkyl ketones, aliphatic, conjugated and propargylic ketones. Under the optimized reaction conditions, secondary alcohols were obtained in high yields and in enantioselectivities up to >99%. The choice of ligand/catalyst allowed for the generation of both enantiomers of the secondary alcohols, where the ruthenium-hydroxyamide and the rhodium-thioamide catalysts act complementarily towards each other. The catalytic systems were also evaluated in the tandem isomerization/asymmetric transfer hydrogenation of racemic allylic alcohols to yield enantiomerically enriched saturated secondary alcohols in up to 98% ee. Furthermore, the catalytic tandem -alkylation/asymmetric transfer hydrogenation of acetophenones and 3-acetylpyridine with primary alcohols as alkylating and reducing agents was studied. Secondary alcohols containing an elongated alkyl chain were obtained in up to 92% ee.

  • 38. Moberg, Christina
    et al.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Concepts in asymmetric catalysis2012Ingår i: Israel Journal of Chemistry, ISSN 0021-2148, Vol. 52, nr 7 SI, s. 571-571Artikel i tidskrift (Refereegranskat)
  • 39.
    Nordin, Mikael
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Ahlford, Katrin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Theoretical study of asymmetric transfer hydrogenation of ketones catalyzed by amino acid derived rhodium complexes2012Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 4, nr 8, s. 1095-1104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Density functional theory calculations are employed to study the asymmetric transfer hydrogenation of ketones catalyzed by rhodiumarene complexes containing hydroxamic acid-functionalized amino acid ligands. Firstly, the ligandmetal binding is investigated and it is shown that both the N,N and O,O binding modes Are viable. For each of these, the full free energy profile for the transfer hydrogenation is calculated according to the outer-sphere reaction mechanism. Three factors are demonstrated to influence the stereoselectivity of the process, namely the energy difference between the metalligand binding modes, the energy difference between the intermediate hydrogenated catalyst, and the existence of a stabilizing CHp interaction between the Cp* ligand of the catalyst and the phenyl moiety of the substrate. Theoretical reproduction of the selectivity of a slightly modified ligand that is shown experimentally to yield the opposite enantioselectivity corroborates these results. Finally, a technical observation made is that inclusion of dispersion interactions (using the B3LYP-D2 correction or the M06 functional) proved to be very important for reproducing the enantioselectivity.

  • 40. Pastor, Isidro
    et al.
    Västilä, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Employing the structural diversity of nature: Development of modular dipeptide-analogue ligands for ruthenium-catalyzed enantioselective transfer-hydrogenation of ketones2003Ingår i: Chemistry a European journal, ISSN 1521-3765, Vol. 9, nr 17, s. 4031-4045Artikel i tidskrift (Refereegranskat)
  • 41. Pastor, Isidro
    et al.
    Västilä, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Novel simple and highly modular ligands for the efficient asymmetric transfer-hydrogenation of ketones2002Ingår i: Chemical Communications, ISSN 1359-7345, nr 18, s. 2046-2047Artikel i tidskrift (Refereegranskat)
  • 42.
    Shatskiy, Andrey
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kivijärvi, Tove
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Propargylic Ketones2015Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, nr 23, s. 3818-3821Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The asymmetric transfer hydrogenation of alpha,beta-propargyl ketones catalyzed by an in situ formed ruthenium-hydroxyamide complex was explored. The acetylenic alcohols were isolated in good to excellent yields with excellent ee values (typically >90%) after short reaction times at room temperature.

  • 43.
    Slagbrand, Tove
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kervefors, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Umeå University, Sweden.
    An Efficient One-pot Procedure for the Direct Preparation of 4,5-Dihydroisoxazoles from Amides2017Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 359, nr 11, s. 1990-1995Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Mo(CO)(6) (molybdenumhexacarbonyl) catalyzed reductive functionalization of amides to afford 5-amino substituted 4,5-dihydroisoxazoles is presented. The reduction of amides generates reactive enamines, which upon the addition of hydroximinoyl chlorides and base undergoes a 1,3-dipolar cycloaddition reaction that gives access to the desired heterocyclic compounds. The transformation of amides is highly chemoselective and tolerates functional groups such as nitro, nitriles, esters, and ketones. Furthermore, a versatile scope of 4,5-dihydroisoxazoles derived from a variety of hydroximinoyl chlorides and amides is demonstrated.

  • 44.
    Slagbrand, Tove
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kivijärvi, Tove
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bimetallic Catalysis: Asymmetric Transfer Hydrogenation of Sterically Hindered Ketones Catalyzed by Ruthenium and Potassium2015Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, nr 21, s. 3445-3449Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An efficient protocol for the asymmetric reduction of sterically hindered ketones under transfer-hydrogenation conditions was developed. The corresponding chiral alcohols were obtained in good to excellent yields with enantiomeric excess values up to 99%. The role of the cation associated with the base present in the reduction reaction was investigated. In contrast to previous studies on this catalyst system, potassium ions rather than lithium ions significantly enhanced the reaction outcome.

  • 45.
    Slagbrand, Tove
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium-Catalyzed Tandem-Isomerization/Asymmetric Transfer Hydrogenation of Allylic Alcohols2014Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 49, s. 16102-16106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A one-pot procedure for the direct conversion of racemic allylic alcohols to enantiomerically enriched saturated alcohols is presented. The tandem-isomerization/asymmetric transfer hydrogenation process is efficiently catalyzed by [{Ru(p-cymene)Cl-2}(2)] in combination with the -amino acid hydroxyamide ligand 1, and performed under mild conditions in a mixture of ethanol and THF. The saturated alcohol products are isolated in good to excellent chemical yields and in enantiomeric excess up to 93%.

  • 46.
    Slagbrand, Tove
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Volkov, Alexey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Trillo, Paz
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tinnis, Fredrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Umeå University, Sweden.
    Transformation of Amides into Highly Functionalized Triazolines2017Ingår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, nr 3, s. 1771-1775Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Triazoles and triazolines are important classes of heterocyclic compounds known to exhibit biological activity. Significant focus has been given to the development of synthetic approaches for the preparation of triazoles, and they are today easily obtainable through a large variety of protocols. The number of synthetic procedures for the formation of triazolines, on the other hand, is limited and further research in this field is required. The protocol presented here gives access to a broad scope of 1,4,5-substituted 1,2,3-triazolines through a one-pot transformation of carboxamides. The two-step procedure involves a Mo(CO)6-catalyzed reduction of tertiary amides to afford the corresponding enamines, followed by in situ cycloaddition of organic azides to form triazolines. The amide reduction is chemoselective and allows for a wide variety of functional groups such as esters, ketones, aldehydes, and imines to be tolerated. Furthermore, a modification of this one-pot procedure gives access to the corresponding triazoles. The chemically stable amide functionality is demonstrated to be an efficient synthetic handle for the formation of highly substituted triazolines or triazoles.

  • 47.
    Tinnis, Fredrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric transfer hydrogenation of ketones catalyzed by rhodium complexes containing amino acid triazole ligands2010Ingår i: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 8, nr 20, s. 4536-4539Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Active and selective catalysts for the asymmetric reduction of ketones, under transfer hydrogenation conditions, were obtained by combining [RhCl2Cp*](2), with a series of L-amino acid thioamide ligands functionalized with 1,2,3-triazoles. The obtained secondary alcohol products were formed with up to 93% ee.

  • 48.
    Tinnis, Fredrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ruthenium catalyzed asymmetric transfer hydrogenation employing novel bidentate abnormal NHC ligands2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    N-Heterocyclic carbenes (NHCs) have been successfully employed as ligands in iridium, rhodium and ruthenium catalyzed transfer hydrogenation reactions. However, there are few reports on the use of catalysts containing chiral NHC ligands for this particular transformation. Furthermore, to the best of our knowledge there are no reports on the use of catalysts based on abnormal NHC ligands in asymmetric transfer hydrogenations. In this work we have prepared novel chiral bidentate NHCs that have the potential for an abnormal binding mode to transitionmetals. Ruthenium complexes of these ligands were employed in the asymmetric transfer hydrogenation of ketones in 2-propanol.

  • 49.
    Tinnis, Fredrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Direct Catalytic Formation of Primary and Tertiary Amides from Non-Activated Carboxylic Acids, Employing Carbamates as Amine Source2012Ingår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, nr 13, s. 2531-2536Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The operationally simple titanium(IV)- or zirconium(IV)-catalyzed direct amidation of non-activated carboxylic acids with ammonium carbamates generates primary, and tertiary N,N-dimethyl-substituted amides in good to excellent yields.

  • 50.
    Tinnis, Fredrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lundberg, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kivijärvi, Tove
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zirconium(IV) Chloride Catalyzed Amide Formation from Carboxylic Acids and Amines: N-Benzyl-2-(phenylthio)acetamide and (S)-tert-butyl-2-(benzylcarbamoyl)pyrrolidine-1-carboxylateManuskript (preprint) (Övrigt vetenskapligt)
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