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  • 1.
    Ahlsten, Nanna
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martin-Matute, Belen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalysed isomerisation of allylic alcohols in water at ambient temperature2010In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 12, no 9, p. 1628-1633Article in journal (Refereed)
    Abstract [en]

    An environmentally benign method for the transformation of allylic alcohols into carbonyl compounds is described. Using [Rh(COD(CH3CN)(2)]BF4 (2) in combination with 1,3,5-triaza-7-phosphaadamantane (PTA, 1) as the catalytic system in water results in a very fast redox isomerisation of a variety of secondary allylic alcohols at ambient temperature. Also, some primary allylic alcohols can be isomerised into the corresponding aldehydes. The active complex, which in some cases can be used in catalyst loadings as low as 0.5 mol%, is formed in situ from commercially available reagents. Based on deuterium labelling studies, a tentative mechanism involving metal-enone intermediates is presented.

  • 2.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    High Throughput Screening of a Catalyst Library for the Asymmetric Transfer Hydrogenation of Heteroaromatic Ketones: Formal Syntheses of (R)-Fluoxetine and (S)-Duloxetine2012In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 4, no 12, p. 2082-2089Article in journal (Refereed)
    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.

  • 3.
    Buitrago, Elina
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Andersson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ryberg, Per
    Aztra Zeneca, Global Process R&D, Södertälje, Sweden.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selective reduction of heteroaromatic ketones: A combinatorial approach2011Conference paper (Other academic)
    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.

  • 4.
    Kovalenko, Oleksandr O.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Huebner, Dennis
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tandem alpha-Alkylation/Asymmetric Transfer Hydrogenation of Acetophenones with Primary Alcohols2014In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 30, p. 6639-6642Article in journal (Refereed)
    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).

  • 5.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Amidst the green Metal-catalyzed amide formation from carboxylic acids2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes novel methods for transition metal-catalyzed transformation of non-activated carboxylic acids to amides. It was found that 2-10 mol% of zirconium(IV) chloride or 10-20 mol% titanium(IV) isopropoxide catalyzed the formation of a range of secondary and tertiary amides in good to excellent yields (61-99%) in THF at 70-100°C, with molecular sieves present as water scavengers. The protocols proved to be suitable for gram scale preparation of amides, where a straight-forward work-up procedure was used for the isolation of the amide products. Furthermore, it was found that ammonium carbamates were suitable equivalents for gaseous ammonia and dimethylamine, in the group (IV) metal-catalyzed amidation of structurally different carboxylic acids, resulting in good to excellent yields (61-99%) of primary and N,N-dimethyl amides.

  • 6.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Group (IV) Metal-Catalyzed Direct Amidation: Synthesis and Mechanistic Considerations2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The amide unit constitutes the backbone of proteins, and it is present in a large number of pharmaceutically active molecules, polymeric materials such as nylon and Kevlar, as well as in food additives like aspartame. Amides are produced in enormous amounts every year, thus, environmentally friendly and selective methods for their formation are of great importance. This thesis deals with the direct formation of amides from non-activated carboxylic acids and amines with the aid of group (IV) metal complexes. Water is the only by-product of this environmentally benign process. This fact stands in contrast to the most common methods for amide formation to date, which involve the use of waste-intensive, expensive and often toxic coupling reagents. The catalytic protocols presented herein use titanium, zirconium and hafnium complexes under mild reaction conditions to produce amides in good to excellent yields. Furthermore, carbamates are demonstrated to be suitable sources of gaseous amines for the formation of primary and tertiary amides under catalytic conditions. In addition, preliminary results from on-going mechanistic investigations of the zirconium- and hafnium-catalyzed processes are presented.

  • 7.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Catalytic α-Alkylation/Reduction of Ketones with Primary Alcohols To Furnish Secondary Alcohols2016In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 48, no 5, p. 644-652Article, review/survey (Refereed)
    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

  • 8.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium-catalyzed asymmetric transfer hydrogenation of ketones in ethanol2011Conference paper (Other academic)
    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).

  • 9.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium-catalyzed asymmetric transfer hydrogenation of ketones in ethanol2011In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, no 21, p. 2754-2758Article in journal (Refereed)
    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).

  • 10.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hans, Adolfsson
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hafnium-Catalyzed Direct Amide Formation at Room Temperature2015In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, no 6, p. 3271-3277Article in journal (Refereed)
    Abstract [en]

    Herein, the first example of a metal-catalyzed protocol for direct amidation of non-activated carboxylic acids at ambient temperature (26 °C) is presented. The mild reaction conditions give rise to high yields of a range of amides in reaction times as short as 90 minutes, employing a commercial hafnium complex, [Hf(Cp)2Cl2], as catalyst. Amino acids are transformed into their corresponding amides without racemization, and the catalyst displays full selectivity for the amidation of carboxylic acids over esters. Electronic properties of the carboxylic acids were found to have a strong influence on the rate of the amidation reaction, and the need for a balanced amount of molecular sieves was observed to be highly important for optimal reaction outcome.

  • 11.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tinnis, Fredrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Direct Amide Coupling of Non-activated Carboxylic Acids and Amines Catalysed by Zirconium(IV) Chloride2012In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 13, p. 3822-3826Article in journal (Refereed)
  • 12.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tinnis, Fredrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Titanium(IV) Isopropoxide as an Efficient Catalyst for Direct Amidation of Nonactivated Carboxylic Acids2012In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 23, no 15, p. 2201-2204Article in journal (Refereed)
    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.

  • 13.
    Lundberg, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tinnis, Fredrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Catalytic amide formation from non-activated carboxylic acids and amines2014In: Chemical Society Reviews, ISSN 0306-0012, E-ISSN 1460-4744, Vol. 43, no 8, p. 2714-2742Article, review/survey (Refereed)
    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.

  • 14.
    Sahoo, Suman
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Lundberg, Helena
    Ahlsten, Nanna
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Martín-Matute, Belén
    Heterogeneous Rh-Catalyzed Reactions of Allylic Alcohols2009Conference paper (Other academic)
    Abstract [en]

    The development of metal-catalyzed reactions that are atom-economical, environmentally benign, and highly selective and that take place under mild reaction conditions is of extreme importance. The isomerization of allylic alcohols to the corresponding carbonyl compounds can be catalyzed by transition metal complexes. We have shown before that this transformation involves the formation of metal enolates. When this isomerization is performed under homogeneous conditions in the presence of an electrophile, a new C-C bond is formed in a regioselective manner.

    1 Here, we present our studies towards the use of immobilized transition metal complexes as heterogeneous catalysts in tandem transformations of allylic alcohols. Different strategies and supports for the immobilization have been compared in this study.

  • 15.
    Sahoo, Suman
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Edén, Mattias
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Physical Chemistry.
    Ahlsten, Nanna
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Wan, Wei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Single Site Supported Cationic Rhodium(I) Complexes for the Selective Redox Isomerization of Allylic Alcohols2012In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 4, no 2, p. 243-250Article in journal (Refereed)
    Abstract [en]

    The isomerization of allylic alcohols to carbonyl compounds by a heterogeneous rhodium complex is reported. Different silica material supports and catalyst/ligand systems were evaluated. The most efficient catalyst in terms of catalytic activity and stability was found to be a cationic rhodium(I) complex with sulfonated phosphine ligands anchored on a mesoporous aluminosilica AlSBA-15. The heterogeneous complex catalyzed the isomerization of a variety of allylic alcohols in excellent yields with very low catalyst loadings (0.5 mol %). The catalyst could be recycled without significant loss of activity or selectivity. The optimized catalyst was characterized by N2 sorption, powder X-ray diffraction, transmission electron microscopy, as well as solution and solid-state nuclear magnetic resonance, and Fourier Transform infrared spectroscopies.

  • 16.
    Shatskiy, Andrey
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kivijärvi, Tove
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Tinnis, Fredrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Propargylic Ketones2015In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, no 23, p. 3818-3821Article in journal (Refereed)
    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.

  • 17.
    Slagbrand, Tove
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ruthenium-Catalyzed Tandem-Isomerization/Asymmetric Transfer Hydrogenation of Allylic Alcohols2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 49, p. 16102-16106Article in journal (Refereed)
    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%.

  • 18.
    Tinnis, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Direct Catalytic Formation of Primary and Tertiary Amides from Non-Activated Carboxylic Acids, Employing Carbamates as Amine Source2012In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 354, no 13, p. 2531-2536Article in journal (Refereed)
    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.

  • 19.
    Tinnis, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kivijärvi, Tove
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zirconium(IV) Chloride Catalyzed Amide Formation from Carboxylic Acids and Amines: N-Benzyl-2-(phenylthio)acetamide and (S)-tert-butyl-2-(benzylcarbamoyl)pyrrolidine-1-carboxylateManuscript (preprint) (Other academic)
  • 20.
    Tinnis, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kivijärvi, Tove
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hans, Adolfsson
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zirconium(IV) chloride catalyzed amide formation from carboxylic acids and amines: N-Benzyl-2-(phenylthio)acetamide and (S)-tert-butyl 2-(benzylcarbamoyl)pyrrolidine-1-carboxylateIn: Organic Syntheses, ISSN 0078-6209Article in journal (Refereed)
  • 21.
    Tinnis, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stridfeldt, Elin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lundberg, Helena
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Stellenbosch University, South Africa.
    Metal-Free N-Arylation of Secondary Amides at Room Temperature2015In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, no 11, p. 2688-2691Article in journal (Refereed)
    Abstract [en]

    The arylation of secondary acyclic amides has been achieved with diaryliodonium salts under mild and metal-free conditions. The methodology has a wide scope, allows synthesis of tertiary amides with highly congested aryl moieties, and avoids the regioselectivity problems observed in reactions with (diacetoxyiodo)benzene.

1 - 21 of 21
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