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  • 1.
    Jiang, Tuo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Quan, Xu
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhu, Can
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Oxidative Synthesis of a-Acetoxylated Enones from Alkynes2016Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 55, nr 19, s. 5824-5828Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report a palladium-catalyzed oxidative functionalization of alkynes to generate -acetoxylated enones in one step. A range of functional groups are well-tolerated in this reaction. Mechanistic studies, including the use of O-18-labeled DMSO, revealed that the ketone oxygen atom in the product originates from DMSO.

  • 2.
    Kerdphon, Sutthichat
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Xu, Quan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Parihar, Vijay Singh
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    C-N Coupling of Amides with Alcohols Catalyzed by N-Heterocyclic Carbene-Phosphine Iridium Complexes2015Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 80, nr 22, s. 11529-11537Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    N-heterocyclic carbene-phosphine iridium complexes (NHC-Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times.

  • 3.
    Li, Jia-Qi
    et al.
    Uppsala University, Sweden.
    Xu, Quan
    Uppsala University, Sweden.
    Andersson, Pher
    Uppsala University, Sweden; University Of KwaZulu-Natal, South Africa.
    Highly Enantioselective Iridium Catalyzed Hydrogenation of α, β-Unsaturated Esters2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 34, s. 10609-10616Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

  • 4.
    Quan, Xu
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hydrogenation, Transfer Hydrogenation and Hydrogen Transfer Reactions Catalyzed by Iridium Complexes2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The work described in this thesis is focused on the development of new bidentate iridium complexes and their applications in the asymmetric reduction of olefins, ketones and imines. Three new types of iridium complexes were synthesized, which included pyridine derived chiral N,P-iridium complexes, achiral NHC complexes and chiral NHC-phosphine complexes. A study of their catalytic applications demonstrated a high efficiency of the N,P-iridium complexes for asymmetric hydrogenation of olefins, with good enantioselectivity. The carbene complexes were found to be very efficient hydrogen transfer mediators capable of abstracting hydrogen from alcohols and subsequently transfer it to other unsaturated bonds. This hydrogen transferring property of the carbene complexes was used in the development of C–C and C–N bond formation reactions via the hydrogen borrowing process. The complexes displayed high catalytic reactivity using 0.5–1.0 mol% of the catalyst and mild reaction conditions. Finally chiral carbene complexes were found to be activated by hydrogen gas. Their corresponding iridium hydride species were able to reduce ketones and imines with high efficiency and enantioselectivity without any additives, base or acid.

  • 5.
    Quan, Xu
    et al.
    Uppsala University, Sweden.
    Parihar, Vijay Singh
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bera, Milan
    University of KwaZulu-Natal, South Africa.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. University of KwaZulu-Natal, South Africa.
    Iridium Catalysts with Chiral Bicyclic Pyridine-Phosphane Ligands for the Asymmetric Hydrogenation of Olefins2014Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2014, nr 1, s. 140-146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    New bicyclic pyridine-phosphane ligands were prepared, and their iridium complexes were evaluated in asymmetric hydrogenation of trisubstituted olefins with non-coordinating and weakly coordinating substituents. The iridium catalysts showed high reactivity and enantioselectivity for both types of olefins.

  • 6.
    Verendel, J. Johan
    et al.
    Uppsala University, Sweden.
    Li, Jia-Qi
    Uppsala University, Sweden.
    Xu, Quan
    Uppsala University, Sweden.
    Peters, Byron
    Uppsala University, Sweden.
    Zhou, Taigang
    Uppsala University, Sweden.
    Gautun, Odd R.
    Norwegian University of Science and Technology (NTNU), Norway.
    Govender, Thavendran
    University of KwaZulu-Natal, South Africa.
    Andersson, Pher G.
    Uppsala University, Sweden; University of KwaZulu-Natal, South Africa.
    Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 21, s. 6507-6513Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

  • 7.
    Xu, Quan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kerdphon, Sutthichat
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    C-C Coupling of Ketones with Methanol Catalyzed by a N-Heterocyclic Carbene-Phosphine Iridium Complex2015Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, s. 3576-3579Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An N-heterocyclic carbene–phosphine iridium complex system was found to be a very efficient catalyst for the methylation of ketone via a hydrogen transfer reaction. Mild conditions together with low catalyst loading (1 mol %) were used for a tandem process which involves the dehydrogenation of methanol, CC bond formation with a ketone, and hydrogenation of the new generated double bond by iridium hydride to give the alkylated product. Using this iridium catalyst system, a number of branched ketones were synthesized with good to excellent conversions and yields.

  • 8.
    Xu, Quan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kerdphon, Sutthichat
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rujirawanich, Janjira
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Krajangsri, Suppachai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly Active Cationic NHC, Phosphine Iridium Catalysts for Base Free Asymmetric Hydrogenation of KetonesManuskript (preprint) (Annet vitenskapelig)
  • 9.
    Xu, Quan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianguo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rabten, Wangchuk
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diomedi, Simone
    Singh, Thishana
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Thiazole, Imidazole and Oxazoline Based N,P-Ligands for Palladium-Catalyzed Cycloisomerization of 1,6-Enynes2016Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 20, s. 3427-3433Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of N,P-ligands were prepared and evaluated in the asymmetric palladium-catalyzed cycloisomerization of allyl propargyl ether substrates. The reactivity and enantioselectivity of the reaction was shown to be highly dependent on the chiral skeleton of the ligand structures with ee's ranging from 22-99 %. The proton source had a significant impact on the enantioselectivity. The generation of palladium hydride from formic acid led to the highest ee. A selectivity model based on a proposed transition state was used to predict and explain the enantiomeric outcome of the reaction.

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