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  • 1. Cele, Zamani E. D.
    et al.
    Sosibo, Sphelele C.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Kruger, Hendrik G.
    Maguire, Glenn E. M.
    Govender, Thavendran
    Catalytic asymmetric carbon-carbon bond forming reactions catalyzed by tetrahydroisoquinoline (TIQ) N,N '-dioxide ligands2013In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 24, no 4, p. 191-195Article in journal (Refereed)
    Abstract [en]

    The use of TIQ-N,N'-dioxide ligands in asymmetric C-C bond forming reactions is described. In the Michael addition of cyclohexane-1,3-dione and malonates to beta,gamma-unsaturated alpha-ketoesters, excellent yields (up to 93%) and moderate to good enantioselectivities (70-89% ee) were obtained. The catalytic hetero-ene reaction of 2-methoxypropene with phenylglyoxal gave the ene product in excellent yield (95%) with moderate enantioselectivity (77% ee). The catalyst system performed well at temperatures ranging from 0 to 30 degrees C and relatively low catalyst loading (0.2-5 mol %) with dichloromethane being the preferred solvent for all reactions.

  • 2. Chakka, Sai Kumar
    et al.
    Francis, Vivian
    Cele, Zamani E. D.
    Sosibo, Sphelele C.
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Kruger, Hendrik G.
    Maguire, Glenn E. M.
    Govender, Thavendran
    Asymmetric conjugate addition of thioglycolate to a range of chalcones using tetrahydroisoquinoline (TIQ) N,N '-dioxide ligands2012In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 23, no 8, p. 616-622Article in journal (Refereed)
    Abstract [en]

    A series of novel TIQ based N,N'-oxide ligands were synthesised and screened for their catalytic activity in the enantioselective conjugate addition of thioglycolate to chalcones. Bulky groups on the side chain of the TIQ backbone provided the highest enantioselectivity of up to 88% with 10 mol % catalyst loading. It was also observed that these reactions proceeded optimally in the presence of dichloromethane as a solvent. Screening of various metals emphasized La(OTf)(3) as the ideal pre-catalyst for this particular reaction.

  • 3. Chakka, Sai Kumar
    et al.
    Peters, Byron K.
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Maguire, Glenn E. M.
    Kruger, Hendrik G.
    Govender, Thavendran
    Iridium-catalyzed asymmetric hydrogenation of olefins using TIQ phosphine-oxazoline ligands2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 18, p. 2295-2301Article in journal (Refereed)
    Abstract [en]

    A novel family of tetrahydroisoquinoline (TIQ) phosphine-oxazoline ligands and four corresponding iridium complexes have been developed and applied to the asymmetric hydrogenation of unfunctionalized olefins. The results showed that the best conversion rates were observed in up to 99% with an enantiomeric excess of 91%.

  • 4.
    Datta, Gopal K.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Nordeman, Patrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Dackenberg, Jakob
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Nilsson, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry. ORGFARM.
    Hallberg, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Enantiopure 2-Aryl-2-Methyl Cyclopentanones by an Asymmetric Chelation-Controlled Heck Reaction Using Aryl Bromides: Increased Preparative Scope and Effect of Ring Size on Reactivity and Selectivity2008In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 19, no 9, p. 1120-1126Article in journal (Refereed)
    Abstract [en]

    Quaternary 2-aryl-2-methyl cyclopentanones were obtained in 85–94% ee via Pd(0)-catalyzed chelation-controlled asymmetric arylation of a cyclopentenyl ether with aryl bromides and subsequent hydrolysis. Two new cyclohexenyl ethers were synthesized and evaluated as Heck substrates with both aryl iodides and bromides under different reaction conditions. Arylations of the six-membered vinyl ether 1-methyl-2-(S)-(cyclohex-1-enyloxymethyl)-pyrrolidine with aryl bromides were achieved with t-Bu3P-promoted palladium catalysis using either classical or microwave heating. Isolated Heck products were also obtained in high diastereoselectivities (94–98% de).

  • 5.
    Dinér, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Catalytic asymmetric chiral lithium amide-promoted epoxide rearrangement: a NMR spectroscopic and kinetic investigation2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 21-22, p. 2733-2739Article in journal (Refereed)
    Abstract [en]

    The lithium amide derived from the chiral diamine (1R,3S,4S)-3-(1-pyrrolidinyl)methyl-2-azabicyclo[2.2.1]heptane, has been reported to catalytically deprotonate cyclohexene oxide and other epoxides, yielding chiral allylic alcohols in excellent enantiomeric excess. In this work, 6Li, 1H and 13 C NMR spectroscopy have been used to study the aggregation of the chiral lithium amide in THF and the influence on the aggregation by the addition of additives, such as 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU). The activated complex under catalytic deprotonation of cyclohexene oxide, that is, with excess Li-DBU and free DBU, is built from one monomer of the chiral lithium amide, one molecule of epoxide and one additional molecule of DBU. The reaction order (0.97) obtained for the bulk base Li-DBU shows an inverse dependence on the concentration, suggesting a deaggregation of the initial mixed dimer to a monomer-based transition state containing a monomer of the lithium amide.

  • 6.
    Hartikka, Antti
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Hojabri, Leila
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bose, Pratim
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Synthesis and application of novel imidazole and 1H-tetrazolic acid containing catalysts in enantioselective organocatalyzed Diels-Alder reactions2009In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 20, no 16, p. 1871-1876Article in journal (Refereed)
    Abstract [en]

    Herein we report studies on the organocatalytic Diels-Alder reaction using a variety of catalysts capable of activating alpha,beta-unsaturated carbonyl compounds for reactions with dienes. The structurally attractive catalysts 4 and 14 were utilized in the enantioselective organocatalytic Diels-Alder reactions. Catalyst 4 provided the products in fair yields and more importantly in good enantioselectivities of up to 83% ee. Catalyst 14 was synthesized in high yield and was assessed in the enantioselective organocatalytic Diels-Alder reaction. Catalyst 14 proved to be a highly active and selective catalyst providing the products in high yield and high enantioselectivities up to 95% ee. (C) 2009 Elsevier Ltd. All rights reserved.

  • 7.
    Hartikka, Antti
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Slosarczyk, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Arvidsson, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Application of novel sulfonamides in enantioselective organocatalyzed cyclopropanation2007In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 18, no 12, p. 1403-1409Article in journal (Refereed)
    Abstract [en]

    Three novel aryl sulfonamides derived from (2S)-indoline-2-carboxylic acid have been obtained and used as organocatalysts. The catalysts incorporate diverse functionality on the phenyl ring, enabling steric, and electronic fine tuning of the catalysts. The catalysts facilitate the reaction between a range of α,β-unsaturated aldehydes and sulfur ylides, thus providing cyclopropane products in enantiomeric excesses of up to 99%.

  • 8.
    Holmberg, Pär
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Karlsson, John
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Enzymatic Kinetic Resolution of 1-(3-furyl)-3-buten-1ol2005In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 16, p. 2397-2399Article in journal (Other academic)
    Abstract [en]

    The enzymatic kinetic resolution of 1-(3-furyl)-3-buten-1-ol was investigated via the enantioselective hydrolysis of the corresponding acetate. Pseudomonas fluorescens (Fluka) was found to give the highest enantiomeric ratios of the 11 lipases screened. At 51% conversion, the ee value (eep) for the product was found to be 89%, giving an enantiomeric ratio (Ep) of 58, while the ee value (ees) for the substrate was 89%, giving an enantiomeric ratio (Ep) of 38.

  • 9. Kawthekar, Rahul B.
    et al.
    Chakka, Sai Kumar
    Francis, Vivian
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Kruger, Hendrik G.
    Maguire, Glenn E. M.
    Govender, Thavendran
    Synthesis of tetrahydroisoquinoline (TIQ)-oxazoline ligands and their application in enantioselective Henry reactions2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 7, p. 846-852Article in journal (Refereed)
    Abstract [en]

    A novel family of eleven new tetrahydroisoquinoline (TIQ)-oxazoline intermediates and five corresponding copper(II) catalysts has been developed and applied to the catalytic asymmetric Henry reaction of various aldehydes with nitromethane to provide beta-hydroxy nitroalkanes in high conversion (>99%) This paper describes the synthesis of the TIQ compounds from L-dihydroxyphenylalanine (L-DOPA) as the starting material The chiral ligands were complexed in situ with various transition metals such as Cu, Sc, Co, Zn, Ni and Mn and tested as a chiral catalyst for the Henry reaction The reaction was optimized in terms of the metal, counter ion, solvent, temperature and over a range of substrates The corresponding catalyst with copper(II) acetate and 2-propanol as the solvent provides the best enantioselectivities (up to 77% ee) of the corresponding nitroalcohol for 4-chlorobenzaldehyde.

  • 10.
    Li, Jia-Qi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Paptchikhine, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Govender, Thavendran
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bicyclic phosphine-thiazole ligands for the asymmetric hydrogenation of olefins2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1328-1333Article in journal (Refereed)
    Abstract [en]

    New bicyclic thiazole-based chiral N,P-chelating ligands were developed. High activities and enantioselectivities were achieved in the iridium-catalyzed asymmetric hydrogenation of olefins with the new ligands.

  • 11. Manner, Sophie
    et al.
    Hansson, Cecilia
    Larsson, Johanna M.
    Oltner, Viveca T.
    Frejd, Torbjoern.
    Asymmetric baker's yeast reductions of bridgehead-substituted bicyclo[2.2.2]octane-2,6-dione derivatives followed by conversion into catalytically active BODOLs for the diethylzinc addition to benzaldehyde.2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 11-12, p. 1374-1381Article in journal (Refereed)
    Abstract [en]

    4-Substituted bicyclo[2.2.2]octane-2,6-diones I [R = acetyl, benzyl, allyl, etc.] have been synthesized and tested as substrates in the enantioselective redn. with baker's yeast to give the corresponding hydroxy ketones II [R = acetyl, benzyl, allyl, etc.]. It was found that the deriv. bearing a TIPSO group at the 4-position was not reduced at all while that with a TBDMSO group gave 87% yield and 46% ee. Other 4-oxy functionalized derivs. were reduced with varying yields (36-87%) and ees (10-82%). The best result was obtained for the 4-Oallyl deriv. (80% yield, 82% ee). The hydroxy ketones carrying the benzyloxy and allyloxy groups at the 4-position were converted into the corresponding BODOLs III [R = allyl, benzyl], which were tested as catalysts in the diethylzinc addn. to benzaldehyde. In this reaction the ees were 90% and 89%, resp., which showed that BODOLs substituted at the 4-position are essentially as good catalysts in this reaction as those bearing a hydrogen. [on SciFinder(R)]

  • 12. Naicker, Tricia
    et al.
    Petzold, Katja
    Singh, Thishana
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Kruger, Hendrik G.
    Maguire, Glenn E.M.
    Govender, Thavendran
    Novel tetrahydroisoquinoline based organocatalysts for asymmetric Diels–Alder reactions: insight into the catalytic mode using ROESY NMR and DFT studies2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 23, p. 2859-2867Article in journal (Refereed)
    Abstract [en]

    For the first time an organocatalyst bearing a secondary nitrogen within a cyclohexane ring has been evaluated in the asymmetric Diels–Alder reaction. This organocatalyst is also the first of its kind based on a (1R,3S)-6,7-dimethoxy-1-phenyl-1,2,3,4-tetrahydroisoquinoline backbone. These catalysts were tested over a range of dienes and dienophiles and displayed promising chemical conversions of up to 100% with up to 64% ee with triflic acid as the cocatalyst. Density functional theory computational studies and 2D NMR spectroscopy were used to determine the structure of the intermediate iminium ion formed between the most efficient catalyst and cinnamaldehyde. The reaction profile for each of the four possibilities in this reaction were calculated and it was found that the iminium intermediate leading to the major product is higher in energy but kinetically preferred. The activation energies of all possible reaction paths were calculated and the results correlated with the observed products. These experiments revealed that the presence of both (E)- and (Z)-isomers of the cinnamaldehyde were contributing factors for the low enantioselectivity of the reaction products.

  • 13. Peters, Byron K.
    et al.
    Chakka, Sai Kumar
    Naicker, Tricia
    Maguire, Glenn E. M.
    Kruger, Hendrik G.
    Andersson, Pher G
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Govender, Thavendran
    Synthesis of tetrahydroisoquinoline-diamine ligands and their application in asymmetric transfer hydrogenation2010In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 21, no 6, p. 679-687Article in journal (Refereed)
    Abstract [en]

    The use of the tetrahydroisoquinoline scaffold is well documented in biologically active compounds. However, reports of the utilisation of tetrahydroisoquinoline compounds in asymmetric catalysis are limited. The synthesis of novel diamine ligands possessing the tetrahydroisoquinoline (tetrahydroisoquinoline) backbone and evaluation of their activity in the asymmetric transfer hydrogenation of acetophenone are presented. The diamine ligands in conjunction with i-PrOH as the hydrogen source and [RhCl2(Cp*)](2) as the metal precursor proved to be the most effective of the tetrahydroisoquinoline derivatives for this catalytic system. Water was found to have a profound influence on the enantioselectivity of the reaction. Optimisation of the amount water, i-PrOH and catalytic loading content rendered the best result of 70% enantioselectivity for the (S)-1-phenylethanol isomer product.

  • 14.
    Sawant, Rajiv T.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Stevenson, Joanne
    Odell, Luke R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Organocatalytic asymmetric cross-aldol reaction of 2-chloroethoxy acetaldehyde: diversity-oriented synthesis of chiral substituted 1,4-dioxanes and morpholines2013In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 24, no 2-3, p. 134-141Article in journal (Refereed)
    Abstract [en]

    Herein we report a facile organocatalytic asymmetric direct cross-aldol reaction of 2-chloroethoxy acetaldehyde with aromatic aldehydes using (S)-(-)-alpha,alpha-diphenyl-2-pyrrolidinemethanol as an organocatalyst to afford anti-2-(2-chloroethoxy)-1-arylpropane-1,3-diols with excellent enantioselectivities (95-98%) and moderate diastereoselectivities (3.5-7:1). The 1,3-diols, obtained after the aldehyde reduction, represent highly functional intermediates that allow for further diversification into both chiral 1,4-dioxanes and morpholines, compounds that frequently display interesting biological activities.

  • 15.
    Trifonova, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    The use of nonactivated iminodienophiles in the stereoselective aza-Diels-Alder reaction2004In: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 15, no 3, p. 445-452Article in journal (Refereed)
    Abstract [en]

    This paper describes the preparation of nitrogen-containing bicycles by the aza-Diels–Alderreaction ofnonactivatediminodienophiles and cyclopentadiene. Readily available starting materials such as (S)-(−)-lactate and l-amino acids were used for the preparation of chiral aldehydes with high enantiomeric excess. The improved oxidation procedure by Dess–Martin periodinane was employed for the synthesis of l-alanine derived phthalimide protected aldehyde 14, which was difficult to obtain in high enantiomeric excess by other methods. The influence of different Lewis acids on the stereoselectivity of the aza-Diels–Alderreactionwas also investigated: It was found that the use of a combination of BF3·Et2O and TFA in the cycloaddition leads to complete racemization of the imine prepared from 14 whereas the use of TiCl4 gives the cycloaddition products 17a and 17b with high enantioselectivity (90%).

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