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Alkene Metathesis: Applications in the Synthesis of Novel Organometallic Complexes, and Mechanistic Investigations

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Alkene Metathesis: Applications in the Synthesis of Novel Organometallic Complexes, and Mechanistic Investigations Alkene metathesis: applications in the synthesis of novel organometallic complexes, and mechanistic investigations Den Naturwissenschaftlichen Fakultäten der Friedrich-Alexander-Universität Erlangen-Nürnberg zur Erlangung des Doktorgrades vorgelegt von Giovanni Pietro Rachiero aus Toronto (Kanada) Als Dissertation genehmigt von den Naturwissenschaftlichen Fakultäten der Universität Erlangen-Nürnberg Tag der mündlichen Prüfung: 02 Oktober 2008 Vorsitzender der Promotionskommission: Prof. Dr. E. Bänsch Erstberichterstatter: Prof. Dr. J. A. Gladysz Zweitberichterstatter: Prof. Dr. H. Gröger A mia madre Telma e mio padre Giovanni Con infinito affetto e gratitudine Ogni Sapienza viene dal Signore ed è sempre con Lui. Siracide 1,1 Die vorliegende Arbeit wurde am Institut für Organische Chemie der Friedrich-Alexander- Universität Erlangen-Nürnberg unter Anleitung von Prof. Dr. John A. Gladysz angefertigt. Acknowledgements First of all I would like to express my sincere gratitude to my supervisor Prof. Dr. John A. Gladysz for giving me the opportunity to carry out research in the field of Alkene Metathesis, and for his constant scientific support. Many thanks to all my past and present colleagues for their help and entertainment. I am grateful to the administrative and technical staff of the Institute of Organic Chemistry of the Friedrich-Alexander University of Erlangen-Nürnberg. A particular thank is for Pamela Engerer and Dr. Frank Hampel. I will be always in debt to my friend Prof. Christine Hahn for her help during my first period in Erlangen and for her suggestions during the writing of this thesis. Thanks to Dr. Deprapasad Mandal and Tobias Fiedler for reading this thesis. A special place is for Katrin. Grazie, tesoro mio. Thanks to my sister Teresa, her husband Agostino, their children Manuela e Giuseppe for their support. I dedicate this thesis to my parents. I thank my Mum Telma and Dad Giovanni for their wonderful love and precious encouragement. Thanks for everything you taught me. vi Table of Contents Zusammenfassung x Abstract xiii List of Figures xvi List of Schemes xxi List of Tables xxiv 1. General Introduction 1 1.1. General concepts 1 1.2. Applications of alkene metathesis 3 1.2.1. Cross metathesis (CM). 3 1.2.2. Ring opening metathesis polymerization (ROMP) . 5 1.2.3. Ring closing metathesis (RCM). 6 1.2.4. Future perspectives of alkene metathesis. 8 1.3. Aims of this work 8 1.4. References and notes 10 2. Mechanistic study on the activity of a Hoveyda-type catalyst 13 2.1. Introduction 13 2.1.1. Chauvin and Hérisson alkene metathesis mechanism. 13 2.1.2. Background of ruthenium technology. 14 2.1.3. Grubbs-type catalysts. 16 2.1.4. Hoveyda-type catalysts. 17 2.2. Project design 19 2.3. Results 20 2.3.1. Syntheses of Hoveyda's second generation catalysts. 20 2.3.2. Mass spectrometry experiments. 24 vii 2.4. Discussion 28 2.4.1. Boomerang mechanism. 28 2.4.2. Mass spectrometry experiments. 30 2.5. Conclusions 37 2.6. Experimental section 38 2.7. References and notes 50 3. Gyroscope-like complexes with doubly trans-spanning bis(pyridine)ligands 54 3.1. Introduction 54 3.1.1. Rope-skipping rotors. 54 3.1.2. Gyroscope-like complexes. 57 3.2. Project design 57 3.3. Results 58 3.3.1. Syntheses of alkene-containing pyridines. 58 3.3.2. Syntheses of alkene-containing bis(pyridine) complexes. 62 3.3.3. Syntheses of gyroscope-like complexes. 70 3.3.4. Substitution reactions. 76 3.3.5. Crystallography. 77 3.4. Discussion 83 3.4.1. Ligands. 83 3.4.2. Complexes. 83 3.4.3. Gyroscope-like complexes. 85 3.4.4. Spectroscopy. 86 3.4.5. Mass spectra and thermal stability. 89 3.4.6. Crystal structures. 89 3.4.7. Future directions. 96 3.5 Conclusions 97 viii 3.6. Experimental section 98 3.7. References and notes 127 4. Novel ruthenium-based carbene complexes 132 4.1. Introduction 132 4.1.1. Developments of ruthenium technology. 132 4.1.2. Carbyne and carbide complexes. 134 4.2. Project design 135 4.3. Results 135 4.3.1. Alkene-containing pyridines. 135 4.3.2. Alkene-containing rhenium complexes. 136 4.3.3. VT NMR experiments with alkene-containing pyridines. 139 4.3.4. VT NMR experiments with alkene-containing rhenium complexes. 153 4.3.5. Preparative reactions. 166 4.4. Discussion 169 4.4.1. Alkene-containing rhenium complexes. 169 4.4.2. Crystal structure. 170 4.4.3. Heterobimetallic ruthenium-rhenium carbyne complexes. 171 4.4.4. Future directions. 172 4.5. Conclusions 173 4.6. Experimental section 174 4.7. References and notes 181 5. Crystallography 185 5.1. Data collection and structure refinement 185 5.2. Data deposition 187 5.3. Crystallographic tables 188 ix 5.4. References and notes 190 Curriculum vitae x Zusammenfassung Kapitel 1 liefert einen Überblick über die Alkenmetathese-Reaktion. Kapitel 2 beschreibt die Aktivität des Hoveyda-Metathese-Katalysators der zweiten Generation mit Hilfe von massenspektrometrischen Untersuchungen. Reduktion von (CD3)2CO mit NaBH4 liefert 2-Propanol-d6 (6-d6, 53%). Reaktion von 6-d6 mit HBr ergibt 2-Brompropan-d6 (3-d6, 63%). Anschließende O-Alkylierung von Salicylaldehyd mit 3-d6 (Base Cs2CO3) führt zu 2-Isopropoxybenzaldehyd-d6 (4-d6, 60%). Wittig- + − Reaktion von 4-d6 (Ph3PCH3 Br , t-BuOK) liefert 2-Isopropoxystyrol-d6 (1-d6, 35%). Nitrierung von Mesitylen-d12 ergibt 1,3,5-Trimethylnitrobenzol-d11 (12-d11, 74%). Katalytische Hydrierung von 12-d11 führt zu 2,4,6-Trimethylanilin-d11 (7-d11, 76%). Kondensation von Glyoxal mit 7-d11 (2 äquiv) liefert das Diimin Glyoxal-bis(2,4,6- trimethylphenylimin)-d22 (9-d22, 90%). Reaktion von 9-d22 mit NaBH4 ergibt das Diamin N,N'-Bis(2,4,6-trimethylphenyl)ethylendiamin-d22 dihydrochlorid (10-d22, 83%). Reaktion von 10-d22 mit HC(OEt)3 führt zu 1,3-Bis(2,4,6-trimethylphenyl)imidazolinium-d22 chlorid (2-d22, 84%). Reaktion von Ru(=CHPh)(PCy3)2(Cl)2 (13) mit 2-d22 (Hexan, t- BuOK) ergibt Ru(=CHPh)(H2IMes-d22)(PCy3)(Cl)2 (14-d22, 57%). Behandlung von 14- d22 mit 1-d6 in Gegenwart von CuCl liefert (H2IMes-d22)(Cl2)Ru=CH-o-OC6H4(i-Pr-d6) (15-d28, 85%). Gemische von 15-d28 und sein natürliches Analogon 15-d0 werden in "Crossover-Experimenten" eingesetzt; abhängig von den Reaktionsbedingungen kann der Katalysator rein oder als Mischung 15-d0/15-d6/15-d22/15-d28 zurückgewonnen werden. Letzteres steht mit einem Bumerang-Mechanismus im Einklang. Kapitel 3 beschreibt die Synthese und Charakterisierung von gyroskopähnlichen Molekülen mit zweifach trans-ständigen Bispyridin-Liganden. Reaktionen von 2,6- NC5H3(CH2Br)2 mit CH2=CHCH2MgBr (1.0 M in Diethylether), und HO(CH2)nCH=CH2 + − (n = a, 1; b, 2; c, 3; d, 4) in Gegenwart von C6H5CH2N(CH3)3 Cl liefern die alkenhaltigen Pyridine 2,6-NC5H3(CH2CH2CH=CH2)2 (21, 60%), bzw. 2,6- xi NC5H3(CH2O(CH2)nCH=CH2)2 (22a-d, 45-55%). Reaktionen von 3,5-NC5H3(COCl)2 mit HO(CH2)nCH=CH2 (n = a, 1; b, 2; c, 3; d, 4; e, 5; f, 6; g, 8) ergeben 3,5- NC5H3(COO(CH2)nCH=CH2)2 (29a-g, 41-90%). Williamson Ether Synthesen von 2,6- NC5H3Br2 und HO(CH2)nCH=CH2 (n = a, 1; b, 2) ergeben 2,6- NC5H3(O(CH2)nCH=CH2)2 (45-55%). Quadratisch-planare Komplexe von einigen der beschriebenen substituierten Pyridine werden synthetisiert. Reaktion von [RhCl(coe)2]2 (coe = Cycloocten) mit 22a ergibt trans- Rh(Cl)(CO)[2,6-NC5H3(CH2OCH2CH=CH2)2]2 (26%). PtCl2 wird mit 22a,b und 29a,c-g versetzt und führt zu trans-PtCl2[2,6-NC5H3(CH2O(CH2)nCH=CH2)2]2 (trans-31a, 88%; trans-31b, 26%), bzw. trans-PtCl2[3,5-NC5H3(COO(CH2)nCH=CH2)2]2 (trans-32a,c-g, 63-94%). Rektionen von trans-(PhCN)2PdCl2 mit 29e und 21 ergeben trans-PdCl2[3,5- NC5H3(COO(CH2)5CH=CH2)2]2 (94%) bzw. trans-PdCl2[2,6- NC5H3(CH2CH2CH=CH2)2]2 (trans-34, 15%). Behandlung von trans-31a,b und trans- 32d-g mit 13 und anschließende Hydrierung (Katalysator Pd/C) ergibt die gyroskopähnlichen Komplexe trans-PtCl2[2,6,2',6'- (NC5H3(CH2O(CH2)2n+2OCH2)2H3C5N)] (trans-35a,b, 10-22%), bzw. trans- PtCl2[3,5,3',5'-(NC5H3(COO(CH2)2n+2COO)2H3C5N)] (trans-36d-g, 14-45%). Die Reaktion von trans-34 mit 13 liefert nach säulenchromatographischer Reinigung trans-PdCl2[2,6,2',6'-(NC5H3((CH2)2CH=CH(CH2)2)2H3C5N)] (trans-37, 55- 58%). Anschließende Hydrierung (Katalysator PtO2) ergibt trans-PdCl2[2,6,2',6'- (NC5H3((CH2)6)2H3C5N)] (trans-38, 58-62%). Die Reaktion von trans-32c mit PhC≡CH, in Gegenwart von CuI, liefert trans-Pt(Cl)(C≡CPh)[3,5-NC5H3(COO(CH2)3CH=CH2)2]2 (trans-39c, 18%). Die Kristallstrukturen von trans-31a, trans-35a, trans-35b, trans-36e, und trans-38 wurden bestimmt und analysiert. Kapitel 4 beschreibt die Reaktivität der Grubbs-Metathese-Katalysatoren der ersten und zweiten Generation mit alkenhaltigen Pyridinen und Rhenium-Komplexen mit Hilfe 5 von NMR Studien. Behandlung von (R)-(η -C5H5)Re(NO)(PPh3)(CH3) ((R)-40) mit xii + – Ph3C PF6 und CH2=CHCH2MgBr (1.0 M in Diethylether) liefert nach Umkristallisation 5 den Butenyl-Rheniumkomplex (R)-(η -C5H5)Re(NO)(PPh3)(CH2CH2CH=CH2) ((R)-45, + – 50%). Analoge Behandlung von (R)-40 mit Ph3C PF6 und CH2=CHCH2CH2MgBr (0.5 M in THF) ergibt nach säulenchromatographischer Reinigung den Pentenyl- 5 Rheniumkomplex (R)-(η -C5H5)Re(NO)(PPh3)(CH2CH2CH2CH=CH2) ((R)-46, 45%). Äquimolare Mengen der alkenhaltigen Rhenium-Komplexe (R)-43, (R)-45, und (R)-46, und alkenhaltige Pyridine 22a, 25b, und 29g werden mit 13 oder Ru(=CHPh)(H2IMes)(PCy3)(Cl)2 versetzt.
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