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ABSTRACT SUPERACID CATALYZED REACTIONS: GENERATION OF REACTIVE INTERMEDIATES AND THEIR CHEMISTRY Makafui Gasonoo, Ph.D. Department of Chemistry and Biochemistry Northern Illinois University, 2017 Douglas A. Klumpp, Director This dissertation describes the use of triflic acid as catalyst for generating reactive intermediates and studying their reactivities under varying reaction conditions. The first chapter is an introduction to the types of organic reactions and acids. This chapter also discusses generation and reactivities of superelectrophiles as well. Chapter 2 discusses the synthesis of 3,3-disubstituted-2-oxindoles from the reaction of a series of acetonyl-substituted 3-hydroxy-2-oxindoles with arene in the presence of triflic acid. These reactions are performed under mild conditions and products isolated in decent yields. In chapter 3, the effects of charge migration in a tetra- and pentacationic superelectrophile is studied. These highly reactive intermediates are reacted with benzene at elevated temperatures. In the absence of benzene, cyclization occurs to produce novel N- heterocyclic compounds. Alcohol precursors are also ionized to generate these reactive intermediates and studied using low-temperature NMR. Chapter 4 talks about the effects of charge-charge repulsion on the aromaticity and anti- aromaticity in fluorenyl and dibenzosuberenyl cations respectively. These cations are generated from ionization of the respective biaryl ketones and dibenzosuberenols with superacid. With increasing charge, there is a corresponding increase in the aromaticity or anti-aromaticity of the respective system. Chapter 5 describes the superacid-promoted synthesis of heterocycle-containing 9,9- diarylfluorenes from biaryl ketones. Products are generally isolated in good yields using mild reaction conditions. Some of these compounds are used in the manufacture of organic light emitting diodes (OLEDs) and other organic-based electronics. NORTHERN ILLINOIS UNIVERSITY DE KALB, ILLINOIS MAY 2017 SUPERACID CATALYZED REACTIONS: GENERATION OF REACTIVE INTERMEDIATES AND THEIR CHEMISTRY BY MAKAFUI GASONOO ©2017 Makafui Gasonoo A DISSERTATION SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY AND BIOCHEMISTRY Doctoral Director: Douglas A. Klumpp ACKNOWLEDGEMENTS First and foremost, all praise and honor to God, the Father, the Son and the Holy Spirit for the strength and guidance given me throughout my life, especially during my education here at Northern Illinois University. I would like to say a big thank you to my family for their prayers, supports and encouragement during my studies, especially my wife for all the sacrifices she made for me. I cannot forget my mum who calls me every weekend and kept reminding me to remain focus and work smartly. I’m grateful and really appreciate it. To my advisor, Dr. Douglas A. Klumpp for allowing me to join his research group and for all the supervision and assistance provided while working in his group. I do not know how best to express my appreciation but can proudly say I joined your group with little-to-no research skills but leaving with tremendous amount of skills and knowledge. My committee members: Dr. Narayan S. Hosmane, Dr. Timothy J. Hagen, Dr. Lee S. Sunderlin and Dr. Dennis Brown also contributed in diverse ways and I’m forever indebted to them as well. For this, I say “akpe” and May the Good Lord bless and protect you all. This acknowledgement cannot be complete without thanking the past and present group members for their amazing support. It was fun and exciting working with you all especially Dr. Rajasekhar R. Naredla. DEDICATION To my adorable wife and daughter TABLE OF CONTENTS Page LIST OF TABLES …………………………………………………………… vii LIST OF FIGURES ………………………………………………………….. viii LIST OF APPENDICES …………………………………………………….. x LIST OF SCHEMES …………………………………………………………. xi LIST OF ABBREVIATIONS………………………………………………… xv Chapter 1. INTRODUCTION …………………………………………………… 1 1.1 Addition Reactions………………………………….……... 1 1.1.1 Electrophilic Addition Reactions……………………….... 1 1.2 Electrophilic Aromatic Substitution Reactions.……………. 2 1.3 Acids……………………………………………………….. 3 1.3.1 Strength of Acids………………………………………… 5 1.3.2 Superacids………………………………………………... 5 1.4. Carbocations………………………………………………. 7 1.4.1 Superelectrophiles and Their Reactivities……………….. 9 2. SYNTHESIS OF FUNCTIONALIZED 2-OXINDOLES BY FRIEDEL-CRAFTS REACTIONS…………………………………… 17 2.1. Introduction ………………………………………………. 17 v Chapter Page 2.2. Results and Discussions …………………………….…….. 20 2.3. Conclusions ……………………………………………….. 33 2.4. Experimental ……………………………………………… 34 3. TETRA- AND PENTACATIONIC ELECTROPHILES AND THEIR CHEMISTRY…………………………………………………. 55 3.1. Introduction ……………………………………………...... 55 3.2. Results and Discussions …………………………………… 57 3.3. Conclusions ……………………………………………….. 88 3.4. Experimental……………………………………………….. 89 4. CHARGE-CHARGE REPULSIVE EFFECTS ON 4n AND 4n+2π-SYSTEMS…………………………………………………….... 106 4.1. Introduction ………………………………………………... 106 4.2. Results and Discussions ……………………………............. 110 4.3. Conclusions ……………………………………………….... 128 4.4. Experimental ……………………………………………… 129 5. SYNTHESIS OF HETEROCYCLE-CONTAINING 9,9-DIARYL- FLUORENES USING SUPERELECTROPHILES………………….. 140 5.1. Introduction ………………………………………………. 140 5.2. Results and Discussions…………………………………… 141 5.3. Conclusions …………………………………………......... 162 vi Chapter Page 5.4. Experimental ……………………………………………… 163 References …………………………………………………………………….. 188 Appendices ……………………………………………………………………. 199 LIST OF TABLES Table Page 1.1 Examples of gitonic and distonic superelectrophiles……………… 10 2.1 Products and isolated yields from the reaction of 3-hydroxy-3- (2-oxopropyl)indolin-2-one, 9 with different arenes………………….. 24 2.2 Products and isolated yields from the reaction of 3-hydroxy-2- oxindoles (10-14) with bromobenzene………………………………… 25 2.3 Products and isolated yields from the reaction of N-heterocyclic 3-hydroxy-2-oxindoles (16–20) with benzene ……………………….. 26 3.1 1H and 13C NMR spectral data for superacid-ionization of alcohol 14 and 19 and fluoride 34……………………………………. 69 3.2 DFT calculated 13C NMR chemical shifts for ions 25, 26, 15, 30 and 31……………………………………………………… 75 3.3 Calculated properties of ions 1, 15, and 20…………………......... 78 4.1 NMR spectra data of fluorenyl cations 12a→12d and 21………. 118 4.2 NMR spectra data of dibenzsuberenyl cations 13a→13c………. 120 5.1 Products and yields from the reaction of arenes with biaryl ketone 1a in triflic acid………………………………………….. 146 5.2 Products and yields from the reaction of benzene with biaryl ketone 1b-1e, 2a, 2c, 3a and 3c in triflic acid…………………… 148 LIST OF FIGURES Figure Page 1.1 Hammett acidity function (Ho) and acidity ranges for some selected superacids………………………………………………… 6 1.2 Generic order of stability for benzylic, allylic, tertiary, secondary and primary carbocations………………………………………….. 8 3.1 Products and yields for reaction of 14 and 19 with/out benzene…. 62 3.2a 13C NMR spectra of tetracationic carbenium ion 15 in FSO3H–SbF5 –SO2ClF at −30 °C with d6-acetone as external standard...………………………………………………………… 70 3.2b 1H NMR spectra of tetracationic carbenium ion 15 in FSO3H–SbF5 –SO2ClF at −30 °C with d6-acetone as external standard………………………………………………………….. 71 3.3a 1H NMR spectra of pentacationic oxonium species 31 in FSO3H–SbF5 –SO2ClF at −30 °C with d6-acetone as external standard…………………………………………………………. 72 3.3b 13C NMR spectra of pentacationic oxonium species 31 in FSO3H–SbF5 –SO2ClF at −30 °C with d6-acetone as external standard………………………………………………………... 73 3.4 Calculated structures and energies (kcal/mol) related to the cyclization of trication 28 to product 22…………………………. 81 3.5 Calculated structures and energies (kcal/mol) related to the cyclization of tetracation 33 to product 24………………………. 83 4.1a 1H NMR spectrum of pyridine-based fluorenyl dication 12b…… 116 4.1b 13C NMR spectrum of pyridine-based fluorenyl dication 12b….. 117 4.2a 1H NMR spectrum of pyrazine-based fluorenyl trication 12c…... 276 ix Figure Page 4.2b 13C NMR spectrum of pyrazine-based fluorenyl trication 12c….. 277 4.3a 1H NMR spectrum of pyrimidine-based fluorenyl trication 12d..... 278 4.3b 13C NMR spectrum of pyrimidine-based fluorenyl trication 12d… 279 4.4a 1H NMR spectrum of bis(fluorenyl cation) 21…………………… 280 4.4b 13C NMR spectrum of bis(fluorenyl cation) 21………………….. 281 4.5a 1H NMR spectrum of dibenzosuberenyl monocation 13a………... 282 4.5b 13C NMR spectrum of dibenzosuberenyl monocation 13a……….. 283 4.6a 1H NMR spectrum of pyridine-based dibenzosuberenyl dication 13b………………………………………………………………... 284 4.6b 13C NMR spectrum of pyridine-based dibenzosuberenyl dication 13b……………………………………………………………….. 285 4.7a 1H NMR spectrum of pyrazine-based dibenzosuberenyl dication 13c……………………………………………………………….. 286 4.7b 13C NMR spectrum of pyrazine-based dibenzosuberenyl dication 13c……………………………………………………………….. 287 5.1a Calculated structures and energies for Friedel-Crafts reactions of monocationic species……………………………………………. 157 5.1b Calculated structures and energies for Friedel-Crafts reactions of dicationic species………………………………………………… 158 5.1c Calculated structures and energies for Friedel-Crafts reactions of tricationic species………………………………………………… 159 LIST OF APPENDICES Appendix Page A. 1H NMR and 13C NMR Spectra of New Compounds from Chapter 2………………………………………………………….. 199 B. 1H NMR and 13C NMR Spectra of New Compounds from Chapter 3..………………………………………………………… 242 C. 1H NMR and 13C NMR Spectra of New and Ionized Compounds from
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