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  • 1.
    Ahlford, Katrin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Livendahl, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Fine-tuning catalytic activity and selectivity-[Rh(amino acid thioamide)] complexes for efficient ketone reduction2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 46, p. 6321-6324Article in journal (Refereed)
    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.

  • 2. Ahmad, Anees
    et al.
    Scarassati, Paulo
    Jalalian, Nazli
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Universidade de São Paulo, Brazil.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Silva, Luiz F., Jr.
    Oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III)2013In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 54, no 43, p. 5818-5820Article in journal (Refereed)
    Abstract [en]

    A novel protocol for the oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III) was developed. This approach uses inexpensive, readily available, and stable chemicals (PhI, mCPBA, and TsOH) giving rearrangement products in yields comparable to those obtained using the more expensive commercially available [hydroxy(tosyloxy)iodo]benzene [HTIB or Koser's reagent]. Additionally, an alternative protocol for the synthesis of 1-methyl-2-tetralone through the one-step epoxidation/rearrangement of 4-methyl-1,2-dihydronaphthalene using mCPBA and TsOH was developed.

  • 3.
    Almesåker, Ann
    et al.
    School of Chemistry and ARC Special Research Centre for Green Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia.
    Scott, J. L.
    Spiccia, L.
    Strauss, C. R.
    One-pot synthesis of tripodal tris(2-aminoethyl)amine derivatives from seven molecular components2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 16, p. 1847-1850Article in journal (Refereed)
    Abstract [en]

    Complex tripodal tris(2-aminoethyl)amine (tren)-based ligands have been prepared in a single-pot reaction of tren with 3 equiv each of cyclohexenone and a benzaldehyde derivative (i.e., from seven components and three molecular types). The highest yield of product was obtained for p-nitrobenzaldehyde, the most electrophilic aldehyde used. (C) 2009 Published by Elsevier Ltd.

  • 4.
    Andaloussi, Mounir
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Moreau, Emmanuel
    Chavignon, Olivier
    Teulade, Jean C.
    A convenient synthesis of linear pyridinoimidazo[1,2-a] pyridine and pyrroloimidazo[1,2-a] pyridine cores2007In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, no 47, p. 8392-8395Article in journal (Refereed)
    Abstract [en]

    Two new imidazo[1,2-a] pyridine derivatives, pyridinoimidazo[1,2-a] pyridine (10) and pyrroloimidazo[1,2-a] pyridine (16), were synthesised from 2-amino-4-methyl-5-nitropyridine (1) by linear cyclisation, making use of dimethylformamide dimethylacetal (DMFDMA) as an agent of vinylamine functionalisation. This report describes first the formation of pyridine and pyrroloimidazopyridine from (1), and then the formation of pyridine-fused and pyrrolo-fused pyridine by the Friedlander method and reductive cyclisation followed by treatment of the resulting adduct with chloroacetaldehyde.

  • 5.
    Andersson, Hans
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Das, Sajal
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gustafsson, Magnus
    Olsson, Roger
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis of substituted 4-pyridones and 4-aminopyridinium salts via a one-pot pyridine synthesis2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 32, p. 4218-4220Article in journal (Refereed)
    Abstract [en]

    Synthesis of substituted 4-benzyloxypyridinium salts by the addition of Grignard reagents to pyridine N-oxides provides an efficient route for obtaining substituted 4-pyridones or 4-aminopyridinium salts.

  • 6.
    Appukkuttan, Prasad
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Axelsson, Linda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Van der Eycken, Erik
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Microwave-assisted, Mo(CO)(6)-mediated, palladium-catalyzed amino-carbonylation of aryl halides using allylamine: from exploration to scale-up2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 39, p. 5625-5628Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed aminocarbonylations of various (hetero)aryl halides with allylamine using Mo(CO)(6) as a solid, in situ CO source, were explored. Microwave-enhanced conditions proved to be highly useful in promoting the conversions in a mere 10-20 min with various (hetero)aryl iodides, bromides and chlorides. The scale-up of a microwave-enhanced aminocarbonylation to 25 mmol scale was performed successfully. (C) 2008 Elsevier Ltd. All rights reserved.

  • 7.
    Axelsson, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Veron, Jean-Baptiste
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Sävmarker, Jonas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Lindh, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Odell, Luke
    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.
    An Improved Palladium(II)-Catalyzed Method for the Synthesis of Aryl Ketones from Aryl Carboxylic Acids and Organonitriles2014In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 55, no 15, p. 2376-2380Article in journal (Refereed)
    Abstract [en]

    A palladium(II)-catalyzed decarboxylative protocol for the synthesis of aryl ketones has been developed. The addition of TFA was shown to improve the reaction yield and employing THF as solvent enabled the use of solid nitriles and in only a small excess. Using this method, five different benzoic acids reacted with a wide range of nitriles to produce 29 diverse (hetero)aryl ketone derivatives in up to 94% yield.

  • 8.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Strategies for fine-tuning the catalytic activity of pincer-complexes2006In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 47, no 50, p. 8999-9001Article in journal (Refereed)
    Abstract [en]

    Various methoxy substituted pincer-complexes were prepared in order to study the substituent effects on the catalytic activity in palladium catalyzed opening of vinyl epoxides and boronation of cinnamyl alcohol. The results clearly show that methoxy substitution at the para-position of the pincer-complex leads to up to fourfold acceleration of the catalytic reactions, while substitution of the side-arms does not change the activity of the complex or leads to a slight deceleration of the catalytic processes.

  • 9.
    Blid, Jan
    et al.
    KTH, Superseded Departments, Chemistry.
    Somfai, Peter
    KTH, Superseded Departments, Chemistry.
    Lewis Acid Mediated [2,3]-Sigmatropic Rearrangement of Allylic Ammonium Ylides2003In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 44, no 15, p. 3159-3162Article in journal (Refereed)
    Abstract [en]

    An investigation of the Lewis acid mediated [2,3]-sigmatropic rearrangement of allylic ammonium ylides has been conducted by employing various bases and boron Lewis acids. Using BBr3 together with the phosphazene base 6, various allylic amines could be rearranged in good yields with low to excellent diastereoselectivity.

  • 10.
    Blomkvist, Björn
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Dinér, Peter
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    HBF4 center dot DEE-catalyzed formation of sulfinyl imines: Synthesis and mechanistic studies2018In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 59, no 13, p. 1249-1253Article in journal (Refereed)
    Abstract [en]

    A mild acid-catalysed method is reported for the formation of sulfinyl imines from tert-butanesulfinamide and aromatic or aliphatic aldehydes using tetrafluoroboric acid diethyletherate (10 mol%) in dichloromethane. Reactions were performed at room temperature and gave the corresponding sulfinyl imines in excellent yield after 2 h. A DFT study was performed and a mechanism for the reaction is postulated. 

  • 11.
    Bogár, Krisztián
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    High-yielding metalloenzymatic dynamic kinetic resolution of fluorinated aryl alcohols2007In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, no 31, p. 5471-5474Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic resolution (DKR) of various fluorinated aryl alcohols by a combination of lipase-catalyzed enzymatic resolution with in situ ruthenium-catalyzed alcohol racemization is described. (R)-Selective Candida antarctica lipase B (CALB) was employed for transesterification of different fluoroaryl alcohols in DKR reactions delivering the corresponding acetates in high yield (97%) with excellent enantiomeric excess (98%).

  • 12.
    Bohman, Björn
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. University of Western Australia, Australia.
    Flematti, Gavin R.
    University of Western Australia, Australia.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Practical one-pot stereospecific preparation of vicinal and 1,3-diols2017In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 58, no 1, p. 75-77Article in journal (Refereed)
    Abstract [en]

    A facile one-pot synthesis providing vicinal diols and 1,3-diols in >95% stereoisomeric purity from commercially available enantiopure hydroxy esters has been developed. The esters were reduced with DIBALH and alkylated in situ with 4-pentenylmagnesium bromide, which after workup generated the title diols as diastereomeric pairs. These pairs were easily separated by preparative chromatography, affording products with retained stereoisomeric purity from the starting materials. This method represents an expedient preparation of many common natural products, such as cerambycid beetle pheromones and intermediates towards bicyclic acetal bark beetle pheromones. (C) 2016 Elsevier Ltd. All rights reserved.

  • 13.
    Borg, Tessie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Timmer, Brian
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    Diastereoselective formation of 2,3,4,5-tetrasubstituted tetrahydrofurans by a Lewis acid promoted addition of C3-substituted 1,3-bis(silyl)propenes to aldehydes2013In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 54, no 30, p. 3916-3918Article in journal (Refereed)
    Abstract [en]

    A mild, efficient, Lewis acid promoted addition of C3-substituted 1,3-bis(silyl)propenes to aldehydes to provide the corresponding 2,3,4,5-tetrasubstituted tetrahydrofurans in excellent stereoselectivity is reported.

  • 14.
    Borén, Linnéa
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Leijondahl, Karin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dynamic Kinetic Asymmetric Transformation of 1,4-diols and Preparation of Trans-2,5-Disubstituted pyrrolidines2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 26, p. 3237-3240Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,4-diols is carried out with Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and a ruthenium catalyst. A β-chloro-substituted 1,4-diol is successfully transformed into an optically pure 1,4-diacetate, which is a highly useful synthetic intermediate. The usefulness of the optically pure 1,4-diacetates is demonstrated by the synthesis of enantiopure 2,5-disubstituted pyrrolidines.

  • 15. Brånalt, J
    et al.
    Kvarnstrom, I
    Classon, B
    Samuelsson, B
    Nillroth, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry.
    Danielson, U. Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry.
    Karlén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Hallberg, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    A convenient synthesis of 1-(S)-[1'-(S)-(t-butyloxycarbonylamino)-2'-phenylethyl]oxirane: a useful building block in the synthesis of HIV protease inhibitors1997In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 38, no 19, p. 3483-3486Article in journal (Refereed)
  • 16. Bui, Hue Thi Buu
    et al.
    Ha, Quy Thi Kim
    Oh, Won Keun
    Vo, Duy Duc
    Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chau, Yen Nguyen Tram
    Tu, Cuc Thi Kim
    Pham, Em Canh
    Tran, Phuong Thao
    Tran, Loan Thi
    Mai, Hieu Van
    Microwave assisted synthesis and cytotoxic activity evaluations of new benzimidazole derivatives2016In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 57, no 8, p. 887-891Article in journal (Refereed)
    Abstract [en]

    Twelve new 2-quinolizinylbenzimidazole and 2-naphthalylbenzimidazole derivatives with various 5- and 6-positioned substituents (aza, H, CH3, Cl, NO2, NH2, OCH3), have been synthesized in moderate to excellent yields via the condensation of 4-oxo-4H-quinolizinecarbaldehyde or naphthalenecarbaldehyde with substituted o-phenylenediamines, o-nitroaniline, and 2,3-pyridinediamine using sodium metabisulfite or sodium hydrosulfite under microwave irradiation. The new benzimidazole derivatives were screened for their cytotoxic activity against the human breast cancer cell line (MCF-7). The results showed on one hand that 2-(substituted quinolizinyl)-1H-benzimidazoles (12bf) were less active (3–6 fold) than the positive control Tamoxifen (CC50 = 6.52 μM), and on the other hand, among the 2-(substituted naphthalyl)-1H-benzimidazoles series (13af), compounds 6,7,8-trimethoxy-3-(5-chloro-1H-benzo[d]imidazol-2-yl)naphthalen-1-ol (13c) (CC50 = 7.48 μM) and 6,7,8-trimethoxy-3-(5-methoxy-1H-benzo[d]imidazol-2-yl)naphthalen-1-ol (13f) (CC50 = 6.43 μM) were found to be as active as Tamoxifen.

  • 17.
    Bäckvall, Jan-Erling
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Evidence for (π-allyl)palladium(II)(quinone) complexes in the palladium-catalyzed 1,4-diacetoxylation of conjugated dienes1988In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 29, no 18, p. 2243-2246Article in journal (Refereed)
    Abstract [en]

    Evidence for a coordination of p-benzoquinone to palladium in [4-acetoxy-η3-(1,2,3)-cyclohexenyl]-palladium(II) complexes was provided by changes of the 1H NMR chemical shift values of the π-allyl protons and a decrease of the spin-lattice relaxation time constant for the p-benzoquinone protons.

    The intermediate (π-allyl)palladium(benzoquinone) complexes previously postulated in palladium-catalyzed 1,4-oxidations of 1,3-dienes were detected by NMR spectroscopy.

  • 18.
    Chen, Shan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Hainan University, China.
    Liu, Fuyan
    Zhang, Kuan
    Huang, Hansheng
    Wang, Huani
    Zhou, Jiaying
    Zhang, Jing
    Gong, Yiwei
    Zhang, Dela
    Chen, Yiping
    Lin, Chang
    Wang, Bo
    An efficient enzymatic aminolysis for kinetic resolution of aromatic alpha-hydroxyl acid in non-aqueous media2016In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 57, no 48, p. 5312-5314Article in journal (Refereed)
    Abstract [en]

    A new and highly efficient enzymatic aminolysis approach for kinetic resolution of aromatic a-hydroxy acid in non-aqueous media has been developed. The corresponding alpha-hydroxyl acid ester was employed as the substrate, and commercially available Candida antarctica lipase B is used as the biocatalyst, anhydrous ammonia is the resolving agent. Reactions can be proceeded smoothly in organic solvent at ambient temperatures. High concentration of substrate is allowed due to the application of organic media and the products are obtained in yields of up to 49% with ee values of up to 99%, and with E value of >300, representing an appealing and promising protocol for large-scale preparations.

  • 19.
    Cheruku, Pradeep
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Church, Tamara L.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Trifonova, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Wartmann, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Access to chiral tertiary amines via the iridium-catalyzed asymmetric hydrogenation of enamines2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 51, p. 7290-7293Article in journal (Refereed)
    Abstract [en]

    The asymmetric hydrogenation of N,N-dialkyl and N-alkyl-N-aryl enamines to chiral tertiary amines was studied. All the N,P-ligated iridium complexes investigated were active catalysts for the reaction, but only those with bicycle-supported oxazoline-phosphine ligands gave reasonable stereoinduction. The best catalyst produced a range of chiral tertiary amines in up to 87% ee.

  • 20.
    Chorell, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Edvinsson, Sofie
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Improved procedure for the enantioselective synthesis of dihydrooxazolo and dihydrothiazolo ring-fused 2-pyridones2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 18, p. 2461-2463Article in journal (Refereed)
    Abstract [en]

    Improved procedures to synthesize enantioselectively analogues of a peptidomimetic scaffold with high biological relevance have been developed. Experimental design led to a general method for the preparation of dihydrooxazolo ring-fused 2-pyridones in good yields and high enantiomeric purity. The knowledge gained from this was also used to improve the microwave-accelerated synthesis of dihydrothiazolo ring-fused 2-pyridones to give complete stereo retention and high yields.

  • 21.
    Csjernyik, Gábor
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    New Efficient Ruthenium Catalysts for Racemization of Alcohols at Room Temperature2004In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, no 36, p. 6799-6802Article in journal (Refereed)
    Abstract [en]

    5-Pentaphenylcyclopentadienyl)RuCl(CO)2 was found to catalyze efficiently the racemization of chiral alcohols such as (S)-1-phenylethanol, (S)-1-phenylpropan-2-ol, (S)-4-phenylbutan-2-ol and (S)-4-methoxy-1-phenylethanol at room temperature in the presence of a base. The catalytic activity of three other Ru(II) complexes was also investigated. The effects of halide and solvent were studied as well.

  • 22.
    Danielsson, Marie
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Wahlström, Karolina
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Undén, Anders
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Protection of the indole nucleus of tryptophan in solid-phase peptide synthesis with a dipeptide that can be cleaved rapidly at physiological pH2011In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, no 44, p. 5876-5879Article in journal (Refereed)
    Abstract [en]

    The synthesis of a new derivative of tryptophan Fmoc-Trp(Boc-Sar-Sar)-OH is described. Fmoc-Trp(Boc-Sar-Sar)-OH is introduced into peptides by solid-phase peptide synthesis and during treatment with TFA at the end of the synthesis, the Boc group is cleaved and the peptide is obtained with the indole nucleus modified with the sarcosinyl-sarcosinyl (Sar-Sar) moiety. This modification will introduce a cationic charge that improves the solubility of the peptide during HPLC purification. The Sar-Sar moiety is cleaved upon exposure to physiological pH. The Boc-Sar-Sar group might, therefore, also find use in the design of pro-drugs of indole-containing compounds.

  • 23. Deiana, Luca
    et al.
    Zhao, Gui-Ling
    Dziedzic, Pawel
    Rios, Ramon
    Vesely, Jan
    Ekström, Jesper
    Córdova, Armando
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    One-pot highly enantioselective catalytic Mannich-type reactions between aldehydes and stable a-amido sulfones: Asymmetric synthesis of b-amino aldehydes and b-amino acids2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 2, p. 234-237Article in journal (Refereed)
    Abstract [en]

    A highly enantioselective catalytic route to carbamate- and benzoate-protected β-amino aldehydes and β-amino acids is presented. The amino acid-catalyzed one-pot asymmetric reaction between unmodified aldehydes and α-amido sulfones gives the corresponding β-amino compounds with up to 95:5 dr and 97–>99% ee.

  • 24.
    Deiana, Luca
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhao, Gui-Ling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzik, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rios, Ramón
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Vesely, Jan
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ekström, Jesper
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    One-pot highly enantioselective catalytic Mannich-type reactions between aldehydes and stable α-amido sulfones: asymmetric synthesis of β-amino aldehydes and β-amino acids2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 2, p. 234-237Article in journal (Refereed)
    Abstract [en]

    A highly enantioselective catalytic route to carbamate- and benzoate-protected beta-amino aldehydes and beta-amino acids is presented. The amino acid-catalyzed one-pot asymmetric reaction between unmodified aldehydes and alpha-amido sulfones gives the corresponding beta-amino compounds with up to 95:5 dr and 97-99%

  • 25.
    Desroses, Matthieu
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Wieckowski, Krzysztof
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Stevens, Marc
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Odell, Luke R.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    A microwave-assisted, propylphosphonic anhydride (T3P (R)) mediated one-pot Fischer indole synthesis2011In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, no 34, p. 4417-4420Article in journal (Refereed)
    Abstract [en]

    A rapid, mild, and high yielding protocol for the Fischer indolization of arylhydrazines with T3P (R) under microwave irradiation is described. Significant features of this method include short reaction times and preparative ease.

  • 26.
    Dziedzic, Pawel
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bartoszewicz, Agnieszka
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Inorganic ammonium salts as catalysts for direct aldol reactions in the presence of water2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 52, p. 7242-7245Article in journal (Refereed)
  • 27.
    Dziedzic, Pawel
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ibrahem, Ismail
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Direct catalytic asymmetric three-component Mannich reactions with dihydroxyacetone: enantioselective synthesis of amino sugar derivatives2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 5, p. 803-807Article in journal (Refereed)
    Abstract [en]

    Highly enantioselective, amino acid-catalyzed, one-pot three-component asymmetric Mannich reactions between dihydroxyacetone, p-anisidine, and aldehydes are presented. The reactions proceeded with high chemo- and stereoselectivity and furnished the corresponding α,α′-dihydroxy-β-aminoketones in high yields with 82–95% ee.

  • 28.
    Edin, Michaela
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Córdova, Armando
    Tandem enantioselective organo- and biocatalysis: a direct entry for the synthesis of enantiomerically pure aldols2004In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, p. 7697-7701Article in journal (Refereed)
  • 29.
    Edvinsson, Sofie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Johansson, Susanne
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Larsson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    An efficient procedure for the synthesis of formylacetic esters2012In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 53, no 50, p. 6819-6821Article in journal (Refereed)
    Abstract [en]

    An efficient synthesis of formylacetic esters via ozonolysis of trans-beta-hydromuconic esters followed by a solid-supported triphenylphosphine reduction has been developed. In addition, an extension toward formylacetic amides and a one-pot preparation of more stable intermediates which can be used for further transformations are also described.

  • 30.
    Eiríksdóttir, Emelía
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Rosenthal-Aizman, Katri
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    An improved synthesis of releasable luciferin-CPP conjugates2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 33, p. 4731-4733Article in journal (Refereed)
    Abstract [en]

    We have improved the synthesis of a previously published luciferin-linker, used in an assay enabling rapid real-time quantification of luciferin–CPP conjugate uptake and cytosolic cargo release. We also present the synthesis of a new luciferin-linker with the same conjugation ability. Both luciferin-linkers are now available via an efficient one-pot procedure.

  • 31. El-Sayed, Ashraf
    et al.
    Unelius, C. Rikard
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Twidle, Andrew
    Mitchell, Vanessa
    Manning, Lee-Anne
    Cole, Lyn
    Suckling, David M
    Flores, Fernanda M
    Zaviezo, Tania
    Bergmann, Jan
    Chrysanthemyl 2-acetoxy-3-methylbutanoate: the sex pheromone of the citrophilous mealybug Pseudococcus calceolariae2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 7, p. 1075-1078Article in journal (Refereed)
    Abstract [en]

    Headspace volatiles collected from virgin females of the citrophilous mealybug, Pseudococcus calceolariae, contain three Compounds not present in the headspace of control samples. The main female-specific compound is identified as[2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-acetoxy-3-methylbutanoate (chrysanthemyl 2-acetoxy-3-methylbutanoate). The other two compounds are identified as [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methanol (chrysanthemol) and [2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl]methyl 2-hydroxy-3-methylbutanoate (chrysanthemyl 2-hydroxy-3-methylbutanoate). Traps baited with 100 mu g and 1000 mu g of chrysanthemyl 2-acetoxy-3-methylbutanoate captured 4- and 20-fold more males than traps baited with virgin females.

  • 32.
    Erlandsson, Mikael
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Undén, Anders
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    3-(4-hydroxymethylphenylsulfanyl)propanoic acid (HMPPA) as a new safety catch linker in solid phase peptide synthesis2006In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 32, no 7, p. 5829-5832Article in journal (Refereed)
    Abstract [en]

    A new safety catch linker, 3-(4-hydroxymethylphenylsulfanyl)propanoic acid (HMPPA), is described for use in solid phase peptide synthesis. The linker is readily synthesized from commercially available chemicals in a more cost efficient way compared to similar reported linkers. The HMPPA linker is easily attached to an amino derivatized solid support followed by on-resin oxidation of the thioether to sulfoxide, thereby making the linker very stable towards strong acid treatment. Final resin cleavage is performed by reductive acidolysis.

  • 33. Flöistrup, Erik
    et al.
    Goede, Patrick
    Strömberg, Roger
    Malm, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Synthesis of estradiol backbone mimics via the Stille reaction using copper(II) oxide as co-reagent2011In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, no 2, p. 209-211Article in journal (Refereed)
    Abstract [en]

    Sterically hindered biaryls and 2-phenylbenzo[b]thiophenes that can serve as templates for mimics of the estradiol backbone were prepared in modest to good yields by the Stille reaction using CuO as a co-reagent. Due to the neutral conditions applied in the Stille reaction, protection strategies were unnecessary for hydroxy containing coupling partners. Ligandless coupling conditions were also evaluated.

  • 34.
    Fournière, Viviane
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cumpstey, Ian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of non-glycosidically linked selenoether pseudodisaccharides2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 16, p. 2127-2129Article in journal (Refereed)
    Abstract [en]

    Non-glycosidically linked disaccharide mimetics with a selenoether functionality linking the two monosaccharide residues have been synthesised. Protected Glc(Se3–3)Glc, Glc(Se3–6)Glc and Glc(Se3–6)Man structures were obtained. Selenium was introduced by displacement of carbohydrate sulfonates with a selenobenzoate anion. Conversion into diselenides by methanolysis of the benzoate and aerial oxidation was followed by reduction of the diselenides to selenolates, and in situ displacement of a second carbohydrate sulfonate in an SN2 reaction to give selenoethers. Glc(Se3–3)Glc and Glc(Se3–6)Glc were also obtained in deprotected form.

  • 35.
    Frigell, Jens
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cumpstey, Ian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    First synthesis of 4a-carba-beta-D-galactofuranose2007In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, no 52, p. 9073-9076Article in journal (Refereed)
  • 36.
    Frigell, Jens
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cumpstey, Ian
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of carbadisaccharide mimics of galactofuranosides2009In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 50, no 36, p. 5142-5144Article in journal (Refereed)
  • 37.
    Hoben, Christine E.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanupp, Lisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Practical chemoenzymatic dynamic kinetic resolution of primary amines via transfer of a readily removable benzyloxycarbonyl group2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 6, p. 977-979Article in journal (Refereed)
  • 38. Hortala, L.
    et al.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Levacher, V.
    Bourguignon, J.
    Dupas, G.
    Acyl transfer of 8-acetoxy-2-oxazolinylquinoline assisted by hydrogen bonding formation2002In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 43, no 6, p. 1027-1029Article in journal (Refereed)
    Abstract [en]

    A significant acceleration of acyl transfer has been achieved on 8-acetoxy-2-oxazolinylquinoline in the presence of benzylamine. Comparison of the aminolysis by the new acylating reagent with that of 8-acetoxyquinoline and 8-acetoxyquinoline-2-carbonitrile has been carried out. The results of these experiments suggest that the proximity of a supplementary basic atom to the ester group increases the participation effect of the basic site mainly by formation of a possible second hydrogen bond. The association constant of benzylamine into the basic cavity of 8-methoxy-2-oxazolinylquinoline (K-d = 80 M-1) has been measured by H-1 NMR titration experiments.

  • 39.
    Howard, Fredrick
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Sawadjoon, Supaporn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Samec, Joseph S. M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    A chemoselective route to either 4-methyl-2,4-diphenyl-2-pentene or 1,1,3-trimethyl-3-phenylindane from 2-phenylpropan-2-ol mediated by BiBr3: a mechanistic study2010In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 51, no 32, p. 4208-4210Article in journal (Refereed)
    Abstract [en]

    The reaction of 2-phenylpropan-2-ol mediated by BiBr3 can, through control of the temp., yield selectively either 4-methyl-2,4-diphenyl-2-pentene or 1,1,3-trimethyl-3-phenylindane. A reaction mechanism that proceeds via 1-methylstyrene is disclosed.

  • 40. Häger, M
    et al.
    Holmberg, K
    YKI – Ytkemiska institutet.
    A substitution reaction in an oil-in-water microemulsion catalyzed by a phase transfer catalyst2000In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 41, p. 1245-1248Article in journal (Refereed)
  • 41.
    Högberg, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Lindmark, Marica
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Isaksson, Dan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Sjödin, Kristina
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Franssen, M
    Jongejan, H
    Wijnberg, J
    de Groot, A
    Formation of hemiacetal esters in lipase-catalysed reactions of vinyl esters with hindered secondary alcohols2000In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 41, no 17, p. 3193-3196Article in journal (Refereed)
  • 42. Ibrahem, Ismail
    et al.
    Samec, Joseph S. M.
    Baeckvall, Jan E.
    Cordova, Armando.
    Enantioselective addition of aldehydes to amines via combined catalytic biomimetic oxidation and organocatalytic C-C bond formation.2005In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 46, no 23, p. 3965-3968Article in journal (Refereed)
    Abstract [en]

    The biomimetic catalytic enantioselective addn. of aldehydes to amines is reported. This was accomplished by combining biomimetic coupled catalytic aerobic oxidn. of amines involving ruthenium-induced dehydrogenation and organocatalytic asym. Mannich reactions. The one-pot reactions furnished β-amino aldehyde and α-amino acid derivs. in high yields with excellent chemoselectivity and enantioselectivity. [on SciFinder(R)]

  • 43. ibrahem, Ismail
    et al.
    Samec, Joseph S M
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Córdiva, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective addition of aldehydes to amines via combined catalytic biomimetic oxidation and organocatalytic C-C- bond formation2005In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 46, no 23, p. 3965-3968Article in journal (Refereed)
    Abstract [en]

    The biomimetic catalytic enantioselective addition of aldehydes to amines is reported. This was accomplished by combining biomimetic coupled catalytic aerobic oxidation of amines involving ruthenium-induced dehydrogenation and organocatalytic asymmetric Mannich reactions. The novel one-pot reactions furnished β-amino aldehyde and α-amino acid derivatives in high yields with excellent chemoselectivity and up to >99% ee.

  • 44.
    Isaksson, Rebecka
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Kumpina, Ilze
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Larhed, Mats
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Wannberg, Johan
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Rapid and straightforward transesterification of sulfonyl carbamates2016In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 57, no 13, p. 1476-1478Article in journal (Refereed)
    Abstract [en]

    A fast and convenient method for the alkoxy exchange of sulfonyl carbamates by simply heating in a chosen alkyl alcohol is described. No catalysts or additives are required. Microwave heating at 100-120 degrees C for 20-60 min resulted in good to excellent yields (53-93%) of alkyl (arylsulfonyl)carbamates where the alkyl part originates from the alcohol solvent. The developed protocol was applied to the synthesis of an angiotensin II type 2 receptor (AT2R) ligand.

  • 45.
    Jönsson, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology.
    Erlandsson, Mikael
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology.
    Undén, Anders
    Stockholm University, Faculty of Science, Department of Neurochemistry and Neurotoxicology.
    Solid-phase synthesis of oxygen-bridged tetrahydropyridones2001In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 42, no 39, p. 6953-6956Article in journal (Refereed)
    Abstract [en]

    A solid-phase approach for the synthesis of oxygen-bridged tetrahydropyridones has been developed. A diamine is attached to Trt-Cl resin and condensed with different aliphatic or aromatic ketones and coumarin-3-carboxylic acid for 20 h and cleaved with 5% TFA in DCM, resulting in tri or tetracyclic products in moderate to high yield.

  • 46.
    Kathiravan, Subban
    et al.
    Linnaeus Univ, Dept Chem & Biomed Sci, Bioorgan & Biophys Chem Lab, SE-39182 Kalmar, Sweden.;Linnaeus Univ, Ctr Biomat Chem, SE-39182 Kalmar, Sweden..
    Nicholls, Ian A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Linnaeus Univ, Dept Chem & Biomed Sci, Bioorgan & Biophys Chem Lab, SE-39182 Kalmar, Sweden.;Linnaeus Univ, Ctr Biomat Chem, SE-39182 Kalmar, Sweden..
    Rhodium(III)-catalysed, redox-neutral C(sp(2))-H alkenylation using pivalimide as a directing group with internal alkynes2017In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 58, no 1, p. 1-4Article in journal (Refereed)
    Abstract [en]

    In the presence of [RhCp*Cl(2)l(2), N-pivaloyl anilines react with internal alkynes to give the corresponding 2-alkenylpivalimides under redox neutral conditions through C-H activation. This redox neutral hydroarylation, which does not require an external organic acid, unlocks a regioselective synthetic route to 2-alkenyl anilines and is generally applicable to diversely substituted electron rich and electron poor pivalimides.

  • 47.
    Kathiravan, Suppan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. Uppsala University.
    Rhodium(III)-catalysed, redox-neutral C(sp(2))-H alkenylation using pivalimide as a directing group with internal alkynes2017In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 58, no 1, p. 1-4Article in journal (Refereed)
    Abstract [en]

    In the presence of [RhCp*Cl(2)l(2), N-pivaloyl anilines react with internal alkynes to give the corresponding 2-alkenylpivalimides under redox neutral conditions through C-H activation. This redox neutral hydroarylation, which does not require an external organic acid, unlocks a regioselective synthetic route to 2-alkenyl anilines and is generally applicable to diversely substituted electron rich and electron poor pivalimides. (C) 2016 Elsevier Ltd. All rights reserved.

  • 48.
    Kato, Koichi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Gustavsson, Sven Ake
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Langström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Asymmetric nitroaldol reaction using nitromethane labeled with C-112008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 41, p. 5837-5839Article in journal (Refereed)
    Abstract [en]

    Nitro [C-11]methane produced from [C-11]O-2 reacted with several aldehydes in the presence of chiral metal catalyst prepared from LaLi3(tris(binaphtoxide)), n-BuLi, H2O, and (R)-binaphtol. The Molar ratios of La, Li, and binaphtol for effective catalysis in the C-11-labeling were 1/4/4.5 and 1/4/6, respectively. The C-11-nitroaldol products were obtained in 3-25% radiochemical yields with 39-51 % ee within 20 min starting from the preparation of nitro[C-11]methane.

  • 49. Kawaguchi, Shin-ichi
    et al.
    Srivastava, Puneet
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Palladium-catalyzed Sonogashira cross-coupling of organic tellurides with alkynes2011In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 52, no 32, p. 4120-4122Article in journal (Refereed)
    Abstract [en]

    Alkyl aryl tellurides and a tellurol ester were used as coupling partners in Pd(0)-catalyzed Sonogashira reactions. Microwave-assisted reactions of alkyl aryl tellurides with alkynes in the presence of Cut and catalytic amounts of Pd(PPh(3))(4) produced alkynyl arenes. Similarly, a tellurol ester on reaction with alkynes afforded alkynyl phenyl ketones in the presence of Cut and a catalytic amount of Pd(PPh(3))(4) at room temperature.

  • 50.
    Khan, Farhan A.
    et al.
    Vienna University of Technology, Austria .
    Rabong, Constantin
    Vienna University of Technology, Austria .
    Jordis, Ulrich
    Vienna University of Technology, Austria .
    Phopase, Jaywant
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Surprising behavior of NXO-peptides toward the lithium hydroxide solvolysis2013In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 54, no 28, p. 3679-3682Article in journal (Refereed)
    Abstract [en]

    An unexpected rearrangement of NXO peptides was observed during solvolysis of the methyl ester using lithium hydroxide as the base. It was found that the NXO-compounds rearranged into semioxamazide derivatives in which the ester is derived from the alcohol used as the reaction solvent.

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