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Li, Jia-Qi
Publications (4 of 4) Show all publications
Verendel, J. J., Li, J.-Q., Quan, X., Peters, B., Zhou, T., Gautun, O. R., . . . Andersson, P. G. (2012). Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes. Chemistry - A European Journal, 18(21), 6507-6513
Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
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2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, p. 6507-6513Article in journal (Refereed) Published
Abstract [en]

Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

Keywords
asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
Li, J.-Q., Xu, Q. & Andersson, P. (2012). Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters. Chemistry - A European Journal, 18(34), 10609-10616
Open this publication in new window or tab >>Highly Enantioselective Iridium-Catalyzed Hydrogenation of α,β-Unsaturated Esters
2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 34, p. 10609-10616Article in journal (Refereed) Published
Abstract [en]

α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-182641 (URN)10.1002/chem.201200907 (DOI)000307387300020 ()22807347 (PubMedID)
Available from: 2012-10-14 Created: 2012-10-14 Last updated: 2017-12-07Bibliographically approved
Li, J.-Q. (2012). Studies of Hydrogenations and Isomerizations of Olefins and Alkylations of Amines Using Iridium Catalysts. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Studies of Hydrogenations and Isomerizations of Olefins and Alkylations of Amines Using Iridium Catalysts
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis describes three types of reactions that were carried out using iridium catalysts.

The first type is the iridium-catalyzed asymmetric hydrogenation of olefins. In paper I, the preparation of a new type of bicyclic thiazole-phosphine based iridium complex was described. The new catalysts have displayed high activity and enantioselectivity in the asymmetric hydrogenation of unfunctionalized olefins. Papers II and III focus on the expansion of the substrate scope for the iridium catalyzed asymmetric hydrogenation in which a number of heterocyclic olefins were evaluated. In paper IV, the enantioselective asymmetric hydrogenation of α, β-unsaturated esters was described. The chiral products bearing tertiary stereogenic centers obtained by hydrogenation have great synthetic value and have been used in the synthesis of pharmaceuticals as well as in the total synthesis of natural products.

The second type is the asymmetric isomerization of allylic alcohols. In paper V, both cis and trans primary allylic alcohols were isomerized to the corresponding β-chiral aldehydes in high enantioselectivities by an N,P-chelating iridium complex.

The third type is the selective mono-N-alkylation of amines with alcohols. In paper VI, a phosphine/NHC based iridium catalyst was synthesized and applied in the alkylation of amines. It is the first time that this type of transformation is carried out at room temperature.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. p. 65
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 982
Keywords
Iridium, Asymmetric, Hydrogenation, Isomerization, Alkylation
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-182647 (URN)978-91-554-8502-3 (ISBN)
Public defence
2012-11-28, B21, BMC, Husaragatan 3, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2012-11-07 Created: 2012-10-14 Last updated: 2013-01-23
Li, J.-Q., Peters, B. & Andersson, P. G. (2011). Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex. Chemistry - A European Journal, 17(40), 11143-11145
Open this publication in new window or tab >>Highly Enantioselective Asymmetric Isomerization of Primary Allylic Alcohols with an Iridium-N,P Complex
2011 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 40, p. 11143-11145Article in journal (Refereed) Published
Keywords
aldehydes, allylic alcohols, asymmetric catalysis, iridium, isomerization, N, P ligands
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-164577 (URN)10.1002/chem.201101524 (DOI)000297013100011 ()
Available from: 2011-12-21 Created: 2011-12-21 Last updated: 2017-12-08Bibliographically approved
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