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Iron-Catalyzed Reactions and X-Ray Absorption Spectroscopic Studies Arnar Guðmundsson Iron-Catalyzed Reactions and X-Ray Absorption Spectroscopic Studies of Palladium- and Iron-Catalyzed Reactions and X-Ray Absorption Spectroscopic Studies of Palladium- and Ruthenium-Catalyzed Reactions and Ruthenium-Catalyzed Studies of Palladium- Absorption Spectroscopic Reactions and X-Ray Iron-Catalyzed Ruthenium-Catalyzed Reactions Arnar Guðmundsson Arnar Guðmundsson was born in Reykjavík, Iceland. After finishing his bachelor studies in biochemistry at the University of Iceland, he moved to Sweden to pursue his masters and doctoral studies under the guidance of Prof. Jan-Erling Bäckvall. ISBN 978-91-7911-264-6 Department of Organic Chemistry Doctoral Thesis in Organic Chemistry at Stockholm University, Sweden 2020 Iron-Catalyzed Reactions and X-Ray Absorption Spectroscopic Studies of Palladium- and Ruthenium-Catalyzed Reactions Arnar Guðmundsson Academic dissertation for the Degree of Doctor of Philosophy in Organic Chemistry at Stockholm University to be publicly defended on Friday 22 January 2021 at 10.00 in Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B. Abstract The focus of this thesis is twofold: The first is on the application of iron catalysis for organic transformations. The second is on the use of in situ X-ray absorption spectroscopy (XAS) to investigate the mechanisms of a heterogeneous palladium- catalyzed reaction and a homogeneous ruthenium-catalyzed reaction. In chapters two, three and four, the use of iron catalyst VI, or its analog X, is described for (I) the DKR of sec-alcohols to produce enantiomerically pure acetates; (II) the cycloisomerization of α-allenols and α-allenic sulfonamides, giving 2,3-dihydrofuran or 2,3-dihydropyrrole products, respectively, with excellent diastereoselectivity; and (III) the aerobic biomimetic oxidation of primary- and secondary alcohols to their respective aldehydes or ketones. In the fifth chapter, XAS is used to elucidate the mechanisms of a Pd(II)-AmP-MCF-catalyzed lactonization reaction of acetylenic acids. The catalyst was known to deactivate during the reaction and the XAS studies identified the cause of this deactivation. A reactivation strategy was subsequently developed based on these findings. In the sixth and final chapter, XAS is used to examine the activation mechanism of a ruthenium racemization catalyst and a ruthenium-acyl intermediate which had previously been speculated to be formed in the activation process was confirmed. Keywords: Iron, XAS, Cycloisomerization, DKR, Oxidation. Stockholm 2020 http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-184285 ISBN 978-91-7911-264-6 ISBN 978-91-7911-265-3 Department of Organic Chemistry Stockholm University, 106 91 Stockholm IRON-CATALYZED REACTIONS AND X-RAY ABSORPTION SPECTROSCOPIC STUDIES OF PALLADIUM- AND RUTHENIUM-CATALYZED REACTIONS Arnar Guðmundsson Iron-Catalyzed Reactions and X-Ray Absorption Spectroscopic Studies of Palladium- and Ruthenium- Catalyzed Reactions Arnar Guðmundsson ©Arnar Guðmundsson, Stockholm University 2020 ISBN print 978-91-7911-264-6 ISBN PDF 978-91-7911-265-3 Cover Picture: "The Pond" by Guðmundsson Productions Printed in Sweden by Universitetsservice US-AB, Stockholm 2020 "All is as thinking makes it so" - Marcus Aurelius Abstract The focus of this thesis is twofold: The first is on the application of iron catalysis for organic transformations. The second is on the use of in situ X-ray absorption spectroscopy (XAS) to investigate the mechanisms of a heterogeneous palladium -catalyzed reaction and a homogeneous ruthenium-catalyzed reaction. In chapters two, three and four, the use of iron catalyst VI, or its analog X, is described for (I) the DKR of sec-alcohols to produce enantiomerically pure acetates; (II) the cycloisomerization of -allenols and -allenic sulfonamides, giving 2,3-dihydrofuran or 2,3-dihydropyrrole products, respectively, with excellent diastereoselectivity; and (III) the aerobic biomimetic oxidation of primary- and secondary alcohols to their respective aldehydes or ketones. In the fifth chapter, XAS is used to elucidate the mechanisms of a Pd(II)-AmP-MCF-catalyzed lactonization reaction of acetylenic acids. The catalyst was known to deactivate during the reaction and the XAS studies identified the cause of this deactivation. A reactivation strategy was subsequently developed based on these findings. In the sixth and final chapter, XAS is used to examine the activation mechanism of a ruthenium racemization catalyst and a ruthenium-acyl intermediate which had previously been speculated to be formed in the activation process was confirmed. i Populärvetenskaplig sammanfattning Avhandlingen omfattar två projektdelar. I den första delen har järnkatalysatorer studerats för att åstadkomma organiska transformatioiner och i den andra delen har röntgenabsorptionsspektroskopi använts för att studera mekanismen av en heterogen palladium-katalyserad reaktion och en homogen rutenium-katalyserad reaktion. Användning av järnföreningar som katalysatorer i organisk syntes har tilldragit sig stort intresse under senare år då järn är mycket billigt och dessutom en miljövänlig metall. I kapitel 2 och 3 används en ny typ av järnkatalysator för dynamisk kinetisk resolvering (DKR) av alkoholer och cykloisomerisering av α-allenoler och α-alleniska sulfonamider. Med hjälp av dessa reaktioner kan man framställa en rad viktiga enantiomert rena alkoholer och heterocykliska föreningar med hög stereoselektivitet. I kapitel 4 har samma typ av järnkomplex använts i en ny biomimetisk oxidation av alkoholer där luft utnyttjas som oxidationsmedel. I kapitel 5 har röntgenabsorptionsspektroskopi använts för att studera mekanismen för en laktonisering som katalyseras av heterogent palladium. Genom denna studie ökade kunskapen om reaktionen och man kunde vidta åtgärder som ledde till en aktiv katalysator där deaktivering minimerades. I kapitel 6 användes röntgenabsorptionsspektroskopi för att undersöka aktiveringen av en ruteniumkatalysator som tidigare använts som racemiceringskatalysator i DKR. Ett intermediat som tidigare föreslagits kunde nu identifieras och med denna metod erhölls bindningsavstånd för intermediatet i lösning. ii List of Publications This thesis is based on the following papers, which will be referred to by the Roman numerals I-VI. Reprints were made with kind permission from the publishers. This thesis is in part based on an earlier half-time report as described in Appendix C along with contribution by the author to each publication. I. Chemoenzymatic Dynamic Kinetic Resolution of Secondary Alcohols Using an Air- and Moisture-Stable Iron Racemization Catalyst Gustafson, K. P. J.; Guðmundsson, A.; Lewis, K.; Bäckvall, J.-E.* Chem. Eur. J. 2017, 23, 1048-1051. II. Efficient Formation of 2,3-Dihydrofurans via Iron-Catalyzed Cycloisomerization of -Allenols Guðmundsson, A.; Gustafson, K. P. J.; Mai, B. K.; Yang, B.;* Himo, F.;* Bäckvall, J.-E.* ACS Catal. 2018, 8, 12-16. III. Diastereoselective Synthesis of N-Protected 2,3- dihydropyrroles via Iron-Catalyzed Cycloisomerization of - Allenic Sulfonamides Guðmundsson, A.;† Gustafson, K. P. J.;† Mai, B.K.; Hobiger, V.; Himo, F.;* Bäckvall, J.-E.* ACS Catal. 2019, 9, 1733-1737. IV. Iron(II)-Catalyzed Aerobic Biomimetic Oxidation of Alcohols Guðmundsson, A.; Schlipköter, K. E.; Bäckvall, J.-E.* Angew. Chem. Int. Ed. 2020, 59, 5403-5406. V. In Situ XAS Investigation of the Deactivation and Reactivation Mechanisms of a Heterogeneous Palladium(II) Catalyst During the Cycloisomerization of Acetylenic Acids Yuan, N.; † Guðmundsson, A.; † Gustafson, K. P. J.; Oschmann, M.; Tai, C.-W.; Persson, I.; Zou, X.; Verho, O.;* Bajnóczi, É. G.;* Bäckvall, J.-E.* Accepted Manuscript iii VI. In Situ Structural Determination of a Homogeneous Ruthenium Racemization Catalyst and its Activated Intermediates Using X-Ray Absorption Spectroscopy Gustafson, K. P. J.;† Guðmundsson, A.;† Bajnóczi, É. G.;† Yuan, N.; Zou, X.;* Persson, I.;* Bäckvall, J.-E.* Chem. Eur. J. 2020, 26, 3411-3419. † Authors contributed equally to the publication. Publications not included in this thesis: Highly Selective Palladium-Catalyzed Hydroborylative Carbocyclization of Bisallenes to Seven-Membered Rings Zhu, C.; Yang, B.; Mai, B. K.; Palazzotto, S.; Qiu, Y.; Guðmundsson, A.; Ricke, A.; Himo, F.;* J.-E. Bäckvall.* J. Am. Chem. Soc. 2018, 140, 14324-14333. Efficient Aerobic Oxidation of Organic Molecules by Multistep Electron Transfer Liu, J.; Guðmundsson, A.; J.-E. Bäckvall.* Accepted Manuscript On the Use of Iron in Organic Chemistry Guðmundsson, A.; J.-E. Bäckvall.* Molecules. 2020, 25, 1349-1368. iv Contents Abstract......................................................................................................................... i Populärvetenskaplig sammanfattning ........................................................................ii List of Publications ....................................................................................................iii Contents ....................................................................................................................... v Abbreviations ............................................................................................................ vii 1. Introduction ............................................................................................................. 1 1.1 Catalysis ......................................................................................................... 1 1.2 Chirality ........................................................................................................
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