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Ir-Catalyzed Asymmetric and Regioselective Hydrogenation of Cyclic Allylsilanes and Generation of Quaternary Stereocenters via the Hosomi-Sakurai Allylation
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.ORCID-id: 0000-0002-1383-8246
2018 (engelsk)Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 24, nr 7, s. 1681-1685Artikkel i tidsskrift (Fagfellevurdert) Published
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.

sted, utgiver, år, opplag, sider
2018. Vol. 24, nr 7, s. 1681-1685
Emneord [en]
allylation, asymmetric reactions, hydrogenation, iridium, regioselectivity
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
URN: urn:nbn:se:su:diva-150597DOI: 10.1002/chem.201704684ISI: 000423804800026OAI: oai:DiVA.org:su-150597DiVA, id: diva2:1169496
Forskningsfinansiär
Stiftelsen Olle Engkvist ByggmästareTilgjengelig fra: 2017-12-27 Laget: 2017-12-27 Sist oppdatert: 2019-12-04bibliografisk kontrollert
Inngår i avhandling
1. The Use of N,P-Iridium and N,P-Palladium Complexes in Asymmetric Synthesis
Åpne denne publikasjonen i ny fane eller vindu >>The Use of N,P-Iridium and N,P-Palladium Complexes in Asymmetric Synthesis
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The work presented in this thesis concerns asymmetric catalysis using chiral N,P-ligands and iridium or palladium transition metals. The first part  (Chapters 2 and 3) highlights the N,P-iridium catalyzed asymmetric hydrogenation of 1,4-cyclohexadienes having functionalized or unfunctionalized substituents, including allylsilane side chains. A series of N,P-iridium catalysts were synthesized and screened on a number of cyclohexadienes. The developed N,P-iridium catalysts have provided excellent chemo-, regio- and enantioselectivity for most of the products obtained. For substrates having an allylsilane sidechain, the chiral cyclic allylsilane products were used to induce stereocontrol in a subsequent Hosomi-Sakurai reaction using TiCl4 as Lewis acid and aldehydes as electrophiles. The corresponding homoallylic alcohols were obtained in good to excellent diastereoselectivity. 

The second part (Chapter 4) describes the N,P-iridium catalyzed asymmetric hydrogenation of various vinyl fluorides. A number of tri- and tetrasubstituted vinyl fluorides were synthesized and evaluated for the asymmetric hydrogenation. The corresponding saturated chiral fluoro compounds were obtained in very high enantioselectivity (up to 99% ee). The defluorination, usually known to occur under the catalytic hydrogenation conditions, were not observed for the majority of the substrates. 

Finally, Chapter 5 describes the application of N,P-ligands in the asymmetric cycloisomerization of 1,6-enynes using a palladium precatalyst. The enantioselectivities for the products were found to depend both on the substrate as well as the hydrogen source. These developed catalytic reactions provide attractive methods to create multiple stereogenic centers in a molecule in relatively few steps from readily available starting materials.

sted, utgiver, år, opplag, sider
Stockholm: Department of Organic Chemistry, Stockholm University, 2018. s. 66
Emneord
Iridium, Asymmetric Hydrogenation, Palladium, Asymmetric Cycloisomerization and Hosomi-Sakurai Allylation
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-150602 (URN)978-91-7797-061-3 (ISBN)978-91-7797-062-0 (ISBN)
Disputas
2018-01-31, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.

Tilgjengelig fra: 2018-01-08 Laget: 2017-12-27 Sist oppdatert: 2018-01-11bibliografisk kontrollert
2. Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins: From Development to Total Synthesis
Åpne denne publikasjonen i ny fane eller vindu >>Enantio- and Regioselective Iridium-Catalyzed Hydrogenation of Olefins: From Development to Total Synthesis
2019 (engelsk)Doktoravhandling, 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. 

sted, utgiver, år, opplag, sider
Stockholm: Department of Organic Chemistry, Stockholm University, 2019. s. 61
Emneord
Asymmetric hydrogenation, Iridium, Regioselectivity, Kinetic resolution, Total synthesis
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-163645 (URN)978-91-7797-588-5 (ISBN)978-91-7797-589-2 (ISBN)
Disputas
2019-03-12, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.

Tilgjengelig fra: 2019-02-15 Laget: 2019-01-23 Sist oppdatert: 2019-02-07bibliografisk kontrollert

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