Iron-Catalyzed Carbon-Carbon Bond Activation Von der Fakultät Chemie der Universität Stuttgart zur Erlangung der Würde eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigte Abhandlung vorgelegt von Che-Hung Lin aus Taipei, Taiwan Hauptberichter: Prof. Dr. Bernd Plietker Mitberichterin: Prof. Dr. Sabine Laschat Tag der mündlichen Prüfung: 31.01.2018 Institut für Organische Chemie der Universität Stuttgart 2018 Die vorliegende Arbeit entstand auf Anregung und unter Anleitung von Herrn Prof. Dr. Bernd Plietker am Institut für Organische Chemie der Universität Stuttgart im Zeitraum von Januar 2014 bis Januar 2018. Parts of this thesis have been published: 1. “The evolution of Fe-catalyzed nucleophilic activation of acceptor-substituted vinyl- and arylcyclopropanes” C.-H. Lin, B. Plietker, Isr. J. Chem. 2016, 56, 409-416. 2. “Non-decarbonylative photochemical versus thermal activation of Bu4N[Fe(CO)3(NO)] - the Fe-catalyzed Cloke-Wilson rearrangement of vinyl and arylcyclopropanes” C.-H. Lin, D. Pursley, J. Klein, J. Teske, J. Allen, F. Rami, A. Köhn, B. Plietker, Chem. Sci. 2015, 6, 7034-7043. i Acknowledgements I would like to express my sincere gratitude to my supervisor, Prof. Dr. Bernd Plietker for giving me an opportunity to join his group, interesting research topics, and excellent working conditions. I would also like to thank my dissertation committee members, Prof. Dr. Sabine Laschat and Prof. Dr. Joris van Slageren form the University of Stuttgart for giving me their great help and priceless advice. I would like to thank all the members of Plietker’s group, Cecilia Socolsky, Dihan Zhang, Johannes Klein, Shih-Fan Hsu, Fiene Horeischi, Christine Häcker, Susanne Rommel, Berenice Heid, Samuel Lorenz, Sven Scholz, Isabel Alt, Dominik Pursley, Johannes Teske, Claudia Guttroff, Fabian Rami, Pascal Eisele, Aslihan Baykal, Marie-Idrissa Picher, Lei Guo, Annika Röske, Franziska Ullwer, Frederik Kramm, and Frank Kraus to provide warm working environments and nice discussions during my PhD. I acknowledge Dominik Pursley’s collaboration for in the investigations of Cloke-Wilson rearrangement. I wish to thank my laboratory mate, Johannes Teske, for his company. The appreciation is also expressed to Isabel Alt, Dihan Zhang, and Lei Guo for the daily life assistance. A special thank also goes to Johannes Teske, Fabian Rami, and Lei Guo for revising my thesis. I am also indebted to all the members of the analytical departments, Ms. Twiehaus- Heynhold, Ms. Wohlbold, Mr. Wegner, Mr. Trinker and Mr. Dr. Frey. ii Erklärung über die Eigenständigkeit der Dissertation Hiermit erkläre ich, dass ich die vorliegende Dissertation „Iron-Catalyzed Carbon-Carbon Bond Activation“ selbstständig verfasst und keine anderen als die genannten Quellen und Hilfsmittel verwendet habe. Die aus fremden Quellen entnommenen Passagen und Gedanken sind als solche kenntlich gemacht. Stuttgart, den 31.01.2018 Che-Hung Lin iii “We can only see a short distance ahead, but we can see plenty there that needs to be done.” ― Alan Turing, Computing machinery and intelligence iv Table of Contents Acknowledgements ...................................................................................................................ii Table of Contents ...................................................................................................................... v List of Abbreviations ................................................................................................................ xii I. Theoretical Section ............................................................................................................... 1 1. Introduction ............................................................................................................................ 2 1.1 Transition-Metal-Catalyzed C-C Bond Activations .................................................... 2 1.2 Iron-Catalyzed C-C Bond Activations ......................................................................... 4 1.3 Synthetic Applications of Three- and Four-Membered Rings ................................. 8 1.3.1 Donor-Acceptor Cyclopropanes ........................................................................ 8 1.3.1.1 Ring-Opening reactions ............................................................................ 9 1.3.1.2 Cycloaddition reactions .......................................................................... 10 1.3.1.3 Rearrangements ...................................................................................... 12 1.3.2 Cyclobutanes ...................................................................................................... 14 1.4 Photochemistry ............................................................................................................. 17 1.4.1 Introduction ......................................................................................................... 17 1.4.2 Photoredox Catalysis ........................................................................................ 19 2. Photoactive Bu4N[Fe(CO)3NO]-Catalyzed Cloke-Wilson Rearrangement of Vinyl- and Arylcyclopropanes .......................................................................................................... 23 2.1 Purpose of this Research ............................................................................................ 23 2.2 Results and Discussion ............................................................................................... 24 2.2.1 Fe-Catalyzed Cloke-Wilson Rearrangement of Vinylcyclopropanes ......... 24 2.2.1.1 Optimization of the Cloke-Wilson Rearrangement of Vinylcyclopropanes............................................................................................... 24 2.2.1.2 Scope of the Cloke-Wilson Rearrangement of Vinylcyclopropanes 26 2.2.2 Fe-Catalyzed Cloke-Wilson Rearrangement of Arylcyclopropanes .......... 32 2.2.2.1 Optimization of the Cloke-Wilson Rearrangement of Arylcyclopropanes ................................................................................................ 32 2.2.2.2 Scope of the Cloke-Wilson Rearrangement of Arylcyclopropanes.. 33 2.2.3 Investigation of the Reaction Mechanism ...................................................... 38 2.3 Conclusion and Outlook .............................................................................................. 47 3. TBA[Fe]-catalyzed Cyclopropylimine Rearrangement ................................................. 49 3.1 Purpose of this Research ............................................................................................ 49 v 3.2 Results and Discussion ............................................................................................... 50 3.2.1 Cyclopropylimine Synthesis ............................................................................. 50 3.2.2 Optimization of the TBA[Fe]-catalyzed Cyclopropylimine Rearrangement ........................................................................................................................................ 52 3.2.3 Substrate Scope of the TBA[Fe]-Catalyzed Cyclopropylimine Rearrangement ............................................................................................................ 55 3.3 Conclusion and Outlook .............................................................................................. 58 4. TBA[Fe]-Catalyzed Cyclobutane Rearrangement ........................................................ 60 4.1 Purpose of this Research ............................................................................................ 60 4.2 Results and Discussion ............................................................................................... 61 4.2.1 Arylcyclobutane Synthesis ............................................................................... 61 4.2.2 TBA[Fe]-catalyzed Arylcyclobutane Rearrangement ................................... 62 4.2.3 Vinylcyclobutane and Vinylcyclobutanone Synthesis .................................. 64 4.2.4 TBA[Fe]-catalyzed Vinylcyclobutane Rearrangement ................................. 69 4.3 Conclusion and Outlook .............................................................................................. 72 5. Summary and Future Work .............................................................................................. 74 6. Abstract (English) ............................................................................................................... 76 7. Abstract (Deutsch) ............................................................................................................. 77 II. Experimental Section ......................................................................................................... 79 8. General Remarks ............................................................................................................... 80 9. IR spectra of TBA[Fe] ........................................................................................................ 81 10. UV spectrum of TBA[Fe] ................................................................................................. 85 11. Fluorescence spectrum of TBA[Fe] .............................................................................. 86 12. TBA[Fe]-Catalyzed Cloke-Wilson Rearrangement of Vinyl- and Arylcyclopropanes ................................................................................................................................................... 87 12.1 Preparation of