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  • 1.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic Regio- and Stereoselective Reactions for the Synthesis of Allylic and Homoallylic Compounds2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis is focused on two main areas of organic synthesis, palladium-catalyzed functionalization of alkenes and allylic alcohols, as well as development of new allylboration reactions.

    We have developed a palladium-catalyzed selective allylic trifluoroacetoxylation reaction based on C−H functionalization. Allylic trifluoroacetates were synthesized from functionalized olefins under oxidative conditions. The reactions proceed under mild conditions with a high level of diastereoselectivity. Mechanistic studies of the allylic C−H trifluoroacetoxylation indicate that the reaction proceeds via (η3-allyl)palladium(IV) intermediate.

    Palladium-catalyzed regio- and stereoselective synthesis of allylboronic acids from allylic alcohols has been demonstrated. Diboronic acid B2(OH)4 was used as the boron source in this process.

    The reactivity of the allylboronic acids were studied in three types of allylboration reactions: allylboration of ketones, imines and acyl hydrazones. All three processes are conducted under mild conditions without any additives. The reactions proceeded with remarkably high regio- and stereoselectivity.

    An asymmetric version of the allylboration of ketones was also developed. In this process chiral BINOL derivatives were used as catalysts. The reaction using γ-disubstituted allylboronic acids and various aromatic and aliphatic ketones afforded homoallylic alcohols bearing two adjacent quaternary stereocenters with excellent regio-, diastereo- and enantioselectivity (up to 97:3 er) in high yield. The stereoselectivity in the allylboration reactions could be rationalized on the basis of the Zimmerman-Traxler TS model.

  • 2.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-catalyzed Allylic C-H and C-OH Functionalization. Reactions of the Obtained Allylboronic Acids2014Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This thesis is focused on the studies of two major transformations. The first transformation deals with the development of palladium-catalyzed selective allylic trifluoroacetoxylation reactions based on C-H functionalization, whereas the second comprises the synthesis and isolation of allylboronic acids using diboronic acid B2(OH)4 as boron source. Both reactions proceed with a very high regio- and stereoselectivity. The mechanistic studies of the allylic C-H trifluoroacetoxylation indicate that the reaction proceeds via (η3-allyl)palladium intermediate.

    The reactivity of the allylboronic acids was studied with ketone and imine substrates. Unlikeother boronates (such as allyl-Bpin derivatives), allylboronic acids react with ketones and imines without any additives under neutral and mild conditions (typically at room temperature). The regio- and stereoselectivity of this reaction is remarkably high. Using functionalized allylboronic acids (prepared in the above mentioned Pd-catalyzed reactions) homoallylic alcohols and amines with adjacent tertiary and quaternary centers could be obtained with high selectivity. Interestingly, both the ketones and the imines reacted with anti-stereoselectivity. This was surprising for the imines. Our mechanistic study has shown that the acyclic aldimines undergo cis/trans isomerization prior to the allylation reaction.

  • 3.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Das, Arindam
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Huang, Genping
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Himo, Fahmi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereoselective allylboration of imines and indoles under mild conditions. An in situ E/Z isomerization of imines by allylboroxines2014Ingår i: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 5, nr 7, s. 2732-2738Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct allylboration of various acyclic and cyclic aldimine, ketimine and indole substrates was performed using allylboronic acids. The reaction proceeds with very high anti-stereoselectivity for both E and Z imines. The allylboroxines formed by dehydration of allylboronic acids have a dual effect: promoting E/Z isomerization of aldimines and triggering the allylation by efficient electron withdrawal from the imine substrate.

  • 4.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diner, Colin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jonker, Sybrand
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic Asymmetric Allylboration of Indoles and Dihydroisoquinolines with Allylboronic Acids: Stereodivergent Synthesis of up to Three Contiguous Stereocenters2016Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 55, nr 46, s. 14417-14421Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The catalytic asymmetric allylboration of cyclic imines with gamma,gamma-disubstituted allylboronic acids provides products with adjacent stereocenters in high yield and stereoselectivity. Various electrophiles, including 3,4-dihydroisoquinolines and indoles, were prenylated in a fully stereodivergent fashion by switching the E/Z geometry of the allylboronate and/or the enantiomer of the BINOL catalyst. 3-Methylindole provided products with three adjacent stereocenters with high stereoselectivity in one synthetic operation.

  • 5.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mihai, Raducan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabo, Kalman J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Selective Formation of Adjacent Stereocenters by Allylboration of Ketones under Mild Neutral Conditions2013Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 15, nr 10, s. 2546-2549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboronic acids readily react with a broad variety of ketones, affording homoallylic alcohols with adjacent quaternary and tertiary stereocenters. The reaction proceeds with very high anti stereoselectivity even if the substituents of the keto group have a similar size. a-Keto acids react with syn stereoselectivity probably due to the formation of acyl boronate intermediates. The allylation reactions proceed without added acids/bases under mild conditions. Because of this, many functionalities are tolerated even with in situ generated allylboronic acids.

  • 6.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pilarski, Lukasz T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pershagen, Elias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabo, Kalman J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereoselective intermolecular allylic C-H trifluoroacetoxylation of functionalized alkenes2012Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, nr 21, s. 8778-8781Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pd-catalyzed allylic C-H trifluoroacetoxylation of substituted alkenes was performed using PhI(OCOCF3)(2) as the oxidant and acyloxy source. Trifluoroacetoxylation of monosubstituted cyclopentenes and cyclohexenes proceeds with excellent regio- and diastereoselectivity. Studies with one of the possible (eta(3)-allyl)Pd(II) intermediates suggest that the reaction proceeds via stereoselective formation of Pd(IV) intermediates and subsequent stereo- and regioselective reductive elimination of the product.

  • 7.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Raducan, Mihai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Diastereoselective allylboration of wide variety of carbonyl compounds using allylboronic acids: Construction of adjacent tertiary and quaternary centers2013Ingår i: Abstracts of papers of The American Chemical Society, American Chemical Society (ACS), 2013, Vol. 246, s. 364-ORGN-Konferensbidrag (Refereegranskat)
  • 8.
    Alam, Rauful
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vollgraff, Tobias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of Adjacent Quaternary Stereocenters by Catalytic Asymmetric Allylboration2015Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 137, nr 35, s. 11262-11265Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboration of ketones with gamma-disubstituted allylboronic acids is performed in the presence of chiral BINOL derivatives. The reaction is suitable for single-step creation of adjacent quaternary stereocenters with high selectivity. We show that, with an appropriate choice of the chiral catalyst and the stereoisomeric prenyl substrate, full control of the stereo- and enantioselectivity is possible in the reaction.

  • 9.
    Das, Arindam
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Stereocontrol in Synthesis of Homoallylic Amines. Syn Selective Direct Allylation of Hydrazones with Allylboronic Acids2014Ingår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 16, nr 14, s. 3808-3811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Allylboronic acids directly react with acyl hydrazones, affording homoallylic amine derivatives. The reaction proceeds with very high syn selectivity, which is the opposite of the stereochemistry observed for allylboration of imines. The reaction can be carried out with both aromatic and aliphatic acyl hydrazones. Based on our studies the excellent syn stereochemistry can be explained by chelation control of the acyl hydrazone and the B(OH)(2) moiety.

  • 10. Miralles, Nuria
    et al.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabó, Kálmán J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Fernandez, Elena
    Transition-Metal-Free Borylation of Allylic and Propargylic Alcohols2016Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 55, nr 13, s. 4303-4307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The base-catalyzed allylic borylation of tertiary allylic alcohols allows the synthesis of 1,1-disubstituted allyl boronates, in moderate to high yield. The unexpected tandem performance of the Lewis acid-base adduct, [Hbase](+)[MeO-B(2)pin(2)](-) favored the formation of 1,2,3-triborylated species from the tertiary allylic alcohols and 1-propargylic cyclohexanol at 90 degrees C.

  • 11.
    Raducan, Mihai
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Alam, Rauful
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Szabo, Kalman J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palladium-Catalyzed Synthesis and Isolation of Functionalized Allylboronic Acids: Selective, Direct Allylboration of Ketones2012Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, nr 52, s. 13050-13053Artikel i tidskrift (Refereegranskat)
1 - 11 av 11
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