Design and Development of Novel Methods for C-H Functionalization for Amination and C-C Bond Formation Open Access

Bon, Jennifer Lynn (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/4j03d021g?locale=en
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Abstract

Building complex molecules from simple starting materials is the heart of organic chemistry. Recently, the functionalization of generally unreactive C-H bonds has been a common target for such transformations due to their ubiquity and the atom economy associated with the transition. A family of ruthenium(II) 2,6-bis(imido)pyridyl complexes was developed for the intermolecular C-H amination of benzylic C-H bonds using sulfamate esters in a racemic fashion. A chiral derivative of the bisimidopyridyl ligand framework was proposed and progress was made toward its synthesis. Separately, molecular recognition was also explored as a means of inducing enantioselectivity in C-H amination reactions. A pyridinebisoxazoline-derived ligand was proposed and progress was made toward its synthesis. Carbon-carbon bond forming reactions for coupling aryl rings are of interest to the medicinal and materials communities. Methodology for the direct coupling of benzobisthiazoles and aryl halides using a copper/palladium co-catalytic system was developed and optimized, and the substrate scope was explored. This was expanded to the synthesis of cruciform structures and the functionalization of thiazolothiazole. Dehydrogenative carbon-carbon bond forming methodology for the synthesis of thiophene substituted benzothiazole derivatives was developed.

Table of Contents

Table of Contents

1 Ruthenium Bis(imido)pyridyl Complexes as Catalysts for Achiral and Chiral Intramolecular Amination ................................................................................................1 1.1 Introduction .............................................................................................................1 1.2 Proposed Ligand Framework ..................................................................................5 1.3 Results and Discussion. ..........................................................................................7 1.4 Optimization ligand design and reaction conditions for amination ......................11 1.5 Examination of substrate scope in C-H amination using catalyst 25 ...................15 1.6 Bis(imido)pyridyl Complexes as Catalysts for Chiral Intramolecular Amination ....................19 1.7 Chiral Ligand Synthesis ........................................................................................20 1.8 Synthesis of Mixed Ferrocenes in a Model System ..............................................24 1.9 Conclusion ............................................................................................................25 2 Intermolecular Amination via a Molecular Recognition Catalyst ....................27 2.1 Introduction ..........................................................................................................27 2.2 Molecular recognition in enantioselective catalysis ............................................29 2.3 Proposed Molecular Recognition Catalyst...........................................................33 2.4 Ligand Synthesis ..................................................................................................34 2.5 Conclusion ...........................................................................................................41 3 Benzodipyrrolidone via C-H Functionalization ...................................................42 3.1 Introduction .........................................................................................................42 3.2 Proposed C-H Functionalization Synthesis .........................................................49 3.3 Synthesis and Exploration of the Model System .................................................52 3.4 Synthesis of BDP core via C-H Functionalization ..............................................54 3.5 Conclusion ..........................................................................................................58 4 Synthesis of 2,6-Difunctionalized Benzobisthiazoles via C-H Functionalization..................................59 4.1 Introduction .........................................................................................................59 4.2 C-H Functionalization of Benzothiazole ...........................................................62 4.3 Initial Exploration of Difunctionalization of BBT .............................................66 4.4 Optimization of coupling conditions .................................................................68 4.5 Probing the Scope of Aryl halides Amenable to the C-H Functionalization of 14.............................................80 4.6 Synthesis of Cruciform Structures via 2,6-Difunctionalization of Benzobisthiazole 14.............................86 4.7 C-H Functionalization of Thiazolothiazole .......................................................91 4.8 Conclusions .........................................................................................................92 5 Dehydrogenative Cross Coupling of Benzothiazole .............................................94 5.1 Introduction .........................................................................................................94 5.2 Results and Discussion .....................................................................................100 5.3 Optimization of dehydrogenative cross coupling of 1 with 2- methylthiophene ................................................................102 5.4 Conclusion .........................................................................................................117 6 Experimental Procedures and Characterization ...............................................119 6.1 General Information ...........................................................................................119 6.2 Chapter 1 Procedures and Characterization .......................................................121 6.3 Chapter 2 Procedures and Characterization .......................................................149 6.4 Chapter 3 Procedures and Characterization ......................................................158 6.5 Chapter 4 Procedures and Characterization ......................................................166 6.6 Chapter 5 Procedures and Characterization .......................................................187 References .......................................................................................................................192

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