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In the first part of this work, a convenient and high yielding synthetic strategy was developed to approach highly electrophilic fluorophosphonium cations as triflate salts. Through in situ electrophilic fluorination of phosphanes with commercially available bench-stable N-fluorobenzenesulfonimide (NFSI), followed by subsequent methylation of the [N(PhSO2)2]- anion with MeOTf, a library of mono-, di- and tri- cationic fluorophosphonium triflates were obtained in excellent yields. The Lewis acidities of all synthesized fluorophosphonium triflates salts were evaluated by both theoretical and experimental methods. These fluorophosphonium triflates have been develop as catalysts for the conversation of formamides into N-sulfonyl formamidines. CHAPTER II of this work focus on developing electrophilic fluorophosphonium cation as Lewis acid pedant in both inter- and intra- molecular FLP systems, as well as exploring their application in small molecular activation and functionalization, such as reversible CO2 sequestration and binding of carbonyls, nitriles and acetylenes. CHAPTER III of this thesis reports on the reaction of electrophilic fluorophosphonium triflates with trimethylsilyl nucleophiles (Me3SiX, X = CN, N3), which selectively yields either pseudohalo-substituted flurophosphoranes or pseudohalo-substituted phosphonium cations.:1. Introduction 1 1.1. Frustrated Lewis Pair chemistry 2 1.2. Phosphorus derivatives as strong Lewis acids 6 2. Objective 11 3. CHAPTER I: Synthesis of fluorophosphonium triflate salts and application as catalyst 15 3.1. Electrophilic fluorination of phosphanes: a convenient approach to electrophilic fluorophosphonium cations 15 3.2. Fluorophilicities and Lewis acidities of the obtained fluorophosphonium derivatives 23 3.2.1. Evaluation of fluorophilicities and Lewis acidities of the obtained fluorophosphonium cations 24 3.2.2. Reactions of fluorophosphonium salts with selected formamides. 27 3.2.3. Reactions of fluorophosphonium salts with selected urea derivatives 31 3.3. Transformation of formamides to N-sulfonyl formamidines using fluorophosphonium triflates as active catalysts 34 4. CHAPTER II: Bifunctional electrophilic fluorophosphonium triflates as intramolecular Frustrated Lewis Pairs 45 5. CHAPTER III: Reaction of fluorophosphonium triflate salts with trimethylsilyl nucleophiles 63 6. Summary 73 7. Perspective 77 8. Experimental section 80 8.1. Materials and methods 80 8.2. Experimental details for CHAPTER I 82 8.2.1. Preparation of imidazoliumyl-substituted phosphanes. 82 8.2.1.1. Preparation of [Ph2LcMeP][OTf] 82 8.2.1.2. Preparation of [Ph2LciPrP][OTf] 83 8.2.1.3. Preparation of [(C6F5)2LcMeP][OTf] 83 8.2.1.4. Preparation of [(C6F5)2LciPrP][OTf] 84 8.2.1.5. Preparation of [PhLcMe2P][OTf]2 85 8.2.1.6. Preparation of [PhLciPr2P][OTf]2 85 8.2.2. Preparation of fluorophosphonium bis(phenylsulfonyl)amide salts 86 8.2.2.1. Preparation of [36(NSI)]. 86 8.2.2.2. Preparation of 58a[NSI] 87 8.2.2.3. Preparation of 58b[N(SO2Ph)2] 88 8.2.3. Preparation of fluorophosphonium triflate salts 88 8.2.3.1. Preparation of 36[OTf] 89 8.2.3.2. Preparation of 36[H(OTf)2] 89 8.2.3.3. Preparation of 58a[OTf] 90 8.2.3.4. Preparation of 58b[OTf] 91 8.2.3.5. Preparation of 58c[OTf] 91 8.2.3.6. Preparation of 59a[OTf] 92 8.2.3.7. Preparation of 59b[OTf] 93 8.2.3.8. Preparation of 60Mea[OTf]2 94 8.2.3.9. Preparation of 60iPra[OTf]2 94 8.2.2.10. Preparation of 60Meb[OTf]2 95 8.2.3.11. Preparation of 60iPrb[OTf]2 96 8.2.3.12. Preparation of 61Me[OTf]3 97 8.2.3.13. Preparation of 61iPr[OTf]3 97 8.2.4. Reaction of fluorophosphonium triflate salts with nucleophiles 98 8.2.4.1. Preparation of 62a[OTf] 98 8.2.4.2. Preparation of 62b[OTf] 99 8.2.4.3. Preparation of 62c[OTf] 100 8.2.4.4. Preparation of 63 100 8.2.4.5. Preparation of 65 101 8.2.4.6. Preparation of 69a[OTf] 102 8.2.4.7. Preparation of 69b[OTf] 103 8.2.5. Synthesis of H[N(SO2R)(SO2Ph)] and corresponding sodium salt 103 8.2.5.1. General procedure for the formation of N-sulfonyl-sulfonamides 103 8.2.5.2. General procedure for the formation of sodium bis(sulfonyl)amides 104 8.2.5.3. Preparation of HN(SO2Ph)2, Na[N(SO2Ph)2] and [nBu4N][N(SO2Ph)2] 104 8.2.5.4. Preparation of 81a and 82a 105 8.2.5.5. Preparation of 81b and 82b 106 8.2.5.6. Preparation of 81c and 82c 106 8.2.5.7. Preparation of 81d and 82d 107 8.2.5.8. Preparation of 81e and 82e 108 8.2.5.9. Preparation of 81f and 82f 108 8.2.5.10. Preparation of 81g and 82g 109 8.2.5.11. Preparation of 81h and 82h 109 8.2.6. Synthesis of N-sulfonyl amidines 110 8.2.6.1. General procedure for the catalytic formation of N-sulfonyl amidines 110 8.2.6.2. Preparation of 64 110 8.2.6.3. Preparation of 72 111 8.2.6.4. Preparation of 73 112 8.2.6.5. Preparation of 74 112 8.2.6.6. Preparation of 75 113 8.2.6.7. Preparation of 76 114 8.2.6.8. Preparation of 77 114 8.2.6.9. Preparation of 78 115 8.2.6.10. Preparation of 79 116 8.2.6.11. Preparation of 80a,b 116 8.2.6.12. Preparation of 83b 117 8.2.6.13. Preparation of 83c 118 8.2.6.14. Preparation of 83d 119 8.2.6.15. Preparation of 83e 119 8.2.6.16. Preparation of 83f 120 8.2.6.17. Preparation of 83g 121 8.2.6.18. Preparation of 83h 122 8.3. Experimental details for CHAPTER II 123 8.3.1. Preparation of N-containing phosphanes 123 8.3.1.1. Preparation of 2-(bis(perfluorophenyl)phosphaneyl)pyridine 123 8.3.1.2. Preparation of 2-(bis(perfluorophenyl)phosphaneyl)-1-methylimidazole 124 8.3.1.3. Preparation of 2-(bis(perfluorophenyl)phosphaneyl)-N,N-dimethylaniline 124 8.3.2. Preparation of N/P Frustrated Lewis Pairs 125 8.3.2.1. General procedure for the synthesis of N/P-Frustrated Lewis pairs 125 8.3.2.2. Preparation of 85[OTf] 126 8.3.2.3. Preparation of 86[OTf] 126 8.3.2.4. Preparation of 87[OTf] 127 8.3.2.5. Preparation of 88[OTf] 128 8.3.2.6. Preparation of 89[OTf] 129 8.3.3. Synthesis of compound 84[OTf] 130 8.3.4. Reaction of N/P FLP with carbonyls, nitriles or acetylenes 131 8.3.4.1. General reaction conditions for the reaction of N/P FLP with carbonyls and nitriles 131 8.3.4.2. Preparation of 90[OTf] 131 8.3.4.3. Preparation of 91[OTf] 132 8.3.4.4. Preparation of 92[OTf] 133 8.3.4.5. Preparation of 93a[OTf] 134 8.3.4.6. Preparation of 93b[OTf] 134 8.3.4.7. Preparation of 94[OTf] 135 8.3.4.8. Preparation of 95[OTf] 136 8.3.4.9. Preparation of 96[OTf] 137 8.3.4.10. Preparation of 97a[OTf] 138 8.3.4.11. Preparation of 97b[OTf] 139 8.3.4.12. Preparation of 99a[OTf]2 140 8.3.4.13 Preparation of 100b[OTf] 141 8.3.5. Reaction of N/P FLPs with CO2 142 8.3.5.1 Reaction of 85[OTf] with CO2 142 8.3.5.2 Reaction of 86[OTf] with CO2 142 8.4. Experimental details for CHAPTER III 144 8.4.1 Synthesis of 105a,b[OTf] and 106c 144 8.4.1.1. General procedure for the reaction of fluorophosphonium triflate with Me3SiCN 144 8.4.1.2. Preparation of 105a[OTf] 144 8.4.1.3. Preparation of 105b[OTf] 145 8.4.1.4. Preparation of 106c 145 8.4.2. Reaction of fluorophosphonium triflate salt with Me3SiN3 146 8.4.2.1. General procedure for preparation of azidofluorophosphorane 146 8.4.2.2. General procedure for preparation of azidofluorophosphonium triflate salts 146 8.4.2.3. Preparation of 107a[OTf] 146 8.4.2.4. Preparation of 107b[OTf] 147 8.4.2.5. Preparation of 107c[OTf] 147 8.4.2.6. Preparation of 108c 148 8.4.2.7. Preparation of 109[OTf] 149 8.4.2.8. Preparation of 110[OTf]2 149 8.4.2.9. Preparation of 113[OTf]3 150 8.4.2.10. Preparation of 114[OTf] 151 8.4.2.11. Preparation of 115[OTf] 151 8.4.2.12. Preparation of 116[OTf] 152 8.4.3 Transformation of azido-fluorophosphorane under heating conditions 153 8.4.3.1 Preparation of 118 153 8.4.3.2 Preparation of 120a,b[OTf] 154 9. Crystallographic details 156 9.1. X-ray Diffraction refinements 156 9.2. Crystallographic details for CHAPTER I 157 9.3. Crystallographic details for CHAPTER II 169 9.4. Crystallographic details for CHAPTER III 176 10. Computational methods 179 11. Abbreviations 181 12. Nomenclature of compounds according to IUPAC recommendations 183 13. References 187 14. Acknowledgment 205 15. Publications and conference contributions 207 15.1. Peer-reviewed publication 207 15.2. Poster presentations 207 Versicherung 209 Erklärung 209 |
