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  • 1.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins: From Development to Total Synthesis2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The work presented in this thesis concerns the iridium-catalyzed asymmetric hydrogenation of cyclic olefins and allylic alcohols for the preparation of useful chiral intermediates with various substitution patterns. The strategy provides stereocontrol for both non-functionalized as well as functionalized substrates and aims to be implemented in the stereoselective preparation of chiral building blocks having more than one stereocenter. The first part (Chapter 2) is focused on the asymmetric hydrogenation of 1,4-cyclohexadienes bearing a number of different functionalities. The development of a novel set of imidazole-based Ir-N,P catalyst enabled the efficient and enantioselective hydrogenation of prochiral substrates. In addition, the challenging regioselective mono-hydrogenation of only one of the two trisubstituted double bonds of the diene was accomplished.

    The sequential preparation of chiral cyclic allylsilanes by means of iridium-catalyzed asymmetric hydrogenation and their employment in the Hosomi-Sakurai reaction was also studied (Chapter 3). Several patterns of alkyl substitution on the prochiral olefins were evaluated and the hydrogenation afforded the allylsilanes in high conversions and excellent enantiomeric excesses. These chiral silanes were then used in the TiCl4-promoted allylation of aldehydes, which took place with high diastereoselectivity.

    In Chapter 4, the kinetic resolution of allylic alcohols via asymmetric hydrogenation is described. High selectivity was observed for a broad range of substrates using a combination of an Ir-N,P catalyst and K2CO3 under mild reaction conditions. This highly efficient process is complementary to our previously reported asymmetric hydrogenation/DKR protocol. The final part (Chapter 5) covers the application of Ir-catalyzed hydrogenations as key steps in total synthesis. A sequential strategy involving enantio- and regioselective hydrogenations was successfully employed in the synthesis of the natural sesquiterpene (-)-Juvabione. In the following project, two allylic alcohols were hydrogenated to prepare chiral intermediates for a convergent formal synthesis of the renin inhibitor Aliskiren. 

  • 2.
    Margarita, Cristiana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Evolution and Prospects of the Asymmetric Hydrogenation of Unfunctionalized Olefins2017Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, nr 4, s. 1346-1356Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The catalytic enantioselective hydrogenation of prochiral olefins is a key reaction in asymmetric synthesis. Its relevance applies to both industry and academia as an inherently direct and sustainable strategy to induce chirality. Here we briefly recount the early breakthroughs concerning the asymmetric hydrogenation of largely unfunctionalized olefins, from the first reports to the advent of chiral Crabtree-like catalysts. The mechanism and its implications on the enantioselectivity are shortly discussed. The main focus of this Perspective lies on the more recent advances in the field, such as the latest developed classes of ligands and the opportunity to employ more Earth-abundant metals. Therefore, separate sections consider iridium N,P-, NHC-, P,S-, and O,P catalysts, and rhodium, palladium, cobalt, and iron catalysts. Finally, the remaining unsolved challenges are examined, and the potential directions of forthcoming research are outlined.

  • 3.
    Margarita, Cristiana
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rabten, Wangchuk
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Transition-Metal-Catalyzed Regioselective Asymmetric Mono-Hydrogenation of Dienes and Polyenes2018Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, nr 32, s. 8022-8028Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organic compounds containing multiple C=C bonds are attractive substrates for catalytic asymmetric hydrogenation. The full saturation of prochiral double bonds, controlling the creation of two or more stereocenters in one step, is obviously a remarkable goal. However, another fascinating and useful option is to selectively introduce a new defined stereogenic center while leaving other double bonds untouched. Thus, the retained functionalities can be further exploited in synthesis. Examples of regio- and enantioselective mono-hydrogenations of polyolefins are highlighted in this Concept article, and are divided according to the nature of the reduced double bond and the transition-metal catalyst used. Alkenes bearing coordinating functional groups are often preferentially hydrogenated by Rh- and Ru-complexes, while the more recently developed Ir-based catalysts promote the selective saturation on alkyl-substituted olefins. Relevant applications of this effective methodology in the synthesis of natural products are included to demonstrate its value in organic synthesis.

  • 4.
    Peters, Byron K.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianguo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Formal Total Synthesis of Aliskiren2015Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, nr 19, s. 7292-7296Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The efficient and selective formal total synthesis of aliskiren is described. Aliskiren, a renin inhibitor drug, has received considerable attention, primarily because it is the first of the renin inhibitor drugs to be approved by the FDA. Herein, the formal synthesis of aliskiren by iridium-catalyzed asymmetric hydrogenation of two allylic alcohol fragments is reported. Screening a number of N,P-ligated iridium catalysts yielded two catalysts that gave the highest enantioselectivity in the hydrogenation, which gave the saturated alcohols in 97 and 93% ee. In only four steps after hydrogenation, the fragments were combined by using the Julia-Kocienski reaction to produce late-stage intermediate in an overall yield of 18%.

  • 5.
    Peters, Byron K.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianguo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rabten, Wangchuk
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kerdphon, Sutthichat
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Orebom, Alexander
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Morsch, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantio- and Regioselective Ir-Catalyzed Hydrogenation of Di- and Trisubstituted Cycloalkenes2016Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 138, nr 36, s. 11930-11935Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A number of cyclic olefins Were prepared and evaluated for the asymmetric hydrogenation reaction using novel N,P-ligated iridium imidazote-based Catalysts (Crabtree type). The diversity of these cyclic olefins spanned those having little functionality to others bearing strongly coordinating substituents and heterocycles. Excellent enantioselectivities were observed both for substrates having little functionality (up to >99% ee) and for substrates possessing functional groups several carbons away from the olefin. Substrates having functionalities such as carboxyl groups, alcohols, or heterocycles in the vicinity of the C=C bond were hydrogenated in high enantiomeric excess (up to >99% ee). The hydrogenation was also found to be regioselective, and by controlling the reaction conditions, selective hydrogenation of one of two trisubstituted olefins can be achieved: Furthermore, trisubstituted olefins can be selectively hydrogenated in the presence of tetrasubstituted olefins.

  • 6.
    Peters, Byron K.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianguo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rabten, Wangchuk
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kerdphon, Sutthichat
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Paptchikhine, Alexander
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantio- and Regioselective Hydrogenation of Minimally and Densely Decorated Unsaturated CarbocyclesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Several cyclic prochiral olefins were successfully hydrogenated (>99 conv.,up to >99 % ee) using N,P-ligated iridium catalysts. Minimally functionalisedsubstrates (Class 1) were hydrogenated rapidly and in high ee, whichwas consistent with earlier reports. Substrates having functional groups(Class 2) and heterocycles (Class 3) attached to the unsaturated cycle, were43hydrogenated gradually over a period of time, however, high enantioselectivitywas still maintained (up to >99 % ee). This methodology is a highly practical,general and selective means of preparing chiral cyclohexanes.

  • 7.
    Rabten, Wangchuk
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ir-Catalyzed Asymmetric and Regioselective Hydrogenation of Cyclic Allylsilanes and Generation of Quaternary Stereocenters via the Hosomi-Sakurai Allylation2018Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, nr 7, s. 1681-1685Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A number of cyclic dienes containing the allylsilane moiety were prepared via Birch reduction and subjected to iridium-catalyzed regioselective and asymmetric hydrogenation, which provided chiral allylsilanes in high conversion and enantiomeric excess (up to 99 % ee). The compounds were successively used in the Hosomi-Sakurai allylation with various aldehydes employing TiCl4 as Lewis acid, providing adducts with two additional stereogenic centers in excellent diastereoselectivity.

  • 8.
    Wu, Haibo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jongcharoenkamol, Jira
    Singh, Thishana
    Nolan, Mark
    Andersson, Pher
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly Efficient Kinetic Resolution of Allylic Alcohols via Iridium-Catalyzed Asymmetric HydrogenationManuskript (preprint) (Annet vitenskapelig)
  • 9.
    Zheng, Jia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Margarita, Cristiana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Krajangsri, Suppachai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Andersson, Pher G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Asymmetric Total Synthesis of (-)-Juvabione via Sequential Ir-Catalyzed Hydrogenations2018Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 20, nr 18, s. 5676-5679Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    (-)-Juvabione, a natural sesquiterpene exhibiting juvenile insect hormone activity, was synthesized constructing the two adjacent stereogenic centers via sequential Ir-catalyzed hydrogenations. The first center is generated by hydrogenation of a styrene-type double bond (99% ee). The successive monohydrogenation of a diene intermediate constitutes the key step, granting high levels of regio- and stereocontrol (94:6 dr). This novel strategy allowed the preparation of (-)-juvabione from simple starting materials in 9 steps and 17% total yield.

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