METHODOLOGY AND MECHANISM REINVESTIGATNG THE ULLMANN REACTION

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TABLE OF CONTENTS
Page
ACKNOWLEDGMENTS.............................................................................................v
ABSTRACT ................................................................................................................vi
LIST OF TABLES ........................................................................................................x
LIST OF FIGURES......................................................................................................xi
CHAPTER
1. PROLOGUE .....................................................................................................1
1.1 Introduction .................................................................................................1
1.2 References ...................................................................................................4
2. FORMATION OF AN UNUSUAL INTRAMOLECULAR C-N BOND:
POSSIBLE C-H ACTIVATION....................................................................................6
2.1 Introduction .................................................................................................6
2.2 Background .................................................................................................7
2.3 Activation of C-H bonds by palladium .........................................................9
2.4 Activation of C-H bonds by palladium specifically at sp3 centers ...............11
2.5 From materials to organometallic chemistry...............................................12
2.6 Conclusion.................................................................................................18
2.7 References .................................................................................................19
3. SYNTHESIS OF UNSYMMETRICAL TRIARYLPHOSPHINES..................23
3.1 Introduction ...............................................................................................23
viii
3.2 Emergence of palladium and nickel catalyzed procedures ..........................24
3.3.Efficacy of copper-based catalysis .............................................................25
3.4 Effect of base in the synthesis of unsymmetrical triarylphosphines.............30
3.5 Optimized protocol and results...................................................................31
3.6 Conclusion.................................................................................................33
3.7 References .................................................................................................34
4. MECHANISM OF THE MODIFIED ULLMANN REACTION......................40
4.1 Introduction ...............................................................................................40
4.2 Background ...............................................................................................42
4.3 Modern improvements to the Ullmann coupling.........................................47
4.4 Mechanistic insights...................................................................................49
4.5 Catalytic cycles involving oxidation state change on the copper catalyst ....50
4.6 Catalytic cycles involving no oxidation state change on the copper catalyst52
4.7 Proof by elimination ..................................................................................54
4.8 Details of kinetics experiments ..................................................................56
4.9 Effect of halides on the well-defined complexes .........................................56
4.10 Effect of added ligands.............................................................................58
4.11 Substituent effects - part 1........................................................................62
4.12 Substituent effects - part 2........................................................................64
4.13 Oxidation state of the catalyst - effects on catalysis ..................................67
4.14 Conclusion...............................................................................................69
4.15 References ...............................................................................................70
ix
5. CONCLUSIONS.............................................................................................76
APPENDIX: EXPERIMENTAL.................................................................................79
BIBLIOGRAPHY.....................................................................................................110