Annulenes, Benzo-, Hetero-, Homo-Derivatives, and their Valence Isomers

Transcription

1 Annulenes, Benzo-, Hetero-, Homo-Derivatives, and their Valence Isomers Volume I Authors Alexandru T. Balaban Professor Department of Organic Chemistry The Polytechnic Bucharest, Romania Mircea Banciu Associate Professor Department of Organic Chemistry The Polytechnic Bucharest, Romania Vasile Ciorba First Economic Secretary West Europe Direction Foreign Trade Ministry Bucharest, Romania CRC Press, Inc. Boca Raton, Florida

2 TABLE OF CONTENTS Chapter 1 Introduction 1 References 2 Chapter 2 Aromaticity of Mono- and Polycyclic Systems 5 I. The History of the Aromatic Sextet from Kekule to Hückel 5 A. Kekule's Benzene Formula 5 B. The Aromatic Sextet 8 II. Kekule Structure Count 13 A. Corrected (Algebraic) Structure Count 13 III. Aromaticity Criteria 14 IV. Resonance Energy of Aromatics 17 V. Aromaticity of Polycyclic Bridged Systems 20 VI. Condensed Benzenoid Polycyclic Hydrocarbons 23 A. Structure, Isomerism, Coding, and Nomenclature 23 B. Radicals, Diradicals, and Related Systems Devoid of Kekule Structures 24 C. Number and Parity of Kekule Structures 25 D. Local Aromaticity 27 E. Relationships Between Structure and Properties Including Carcinogenicity 28 F. Conclusions 29 References 30 Chapter 3 Graph Theory as a Key Tool for the Definition and Enumeration of Valence Isomers 35 I. Graph-Theoretical Preliminaries 35 II. Interplay Between Graph Theory and Chemistry 37 III. Chemistry as a Breeding Ground for Graph Theory 38 IV. Definition of Valence Isomers 39 V. Finding all Possible Valence Isomers of Annulenes (CH) n and of Homoannulenes 40 VI. Pölya's Theorem and Valence Isomers of Heteroannulenes 46

3 VII. Finding Benzoderivatives of Valence Isomers of [n]annulenes 54 VIII. Finding all Possible Isomers of Benzenoid Polycyclic Condensed Hydrocarbons 61 References 63 Chapter 4 Annulenes 67 I. Introduction 67 II. Cyclobutadiene (CBD) 69 A. Substituted Derivatives of Cyclobutadiene 73 B. Metallic Complexes of CBD 77 III. [6]Annulene or Benzene 80 IV. [8]Annulene or Cyclooctatetraene (COT) 80 A. Substituted COT Derivatives 81 V. [10]Annulene or Cyclodecapentaene 87 VI. Larger [n]annuienes (n 5= 12) 90 A. Synthesis via Oxidative Coupling of Terminal Acetylenes 90 B. Photoirradiation of Polycyclic Valence Tautomers 91 C. [12] Annulene 92 D. [14]Annulene 92 E. [16]Annulene 93 F. [18]Annulene 94 G. [20]Annulene 97 H. [22]Annulene 97 I. [24]Annulene 97 J. [30]Annulene 97 K. Conclusions for Macrocyclic Annulenes 97 VII. General Conclusions for Annulenes 98 VIII. Dehydroannulenes 99 A. Introduction 99 B. Syntheses 100 C. 12-Membered Rings 103 D. 14-Membered Rings 103 E. 16-Membered Rings 105 F. 18-Membered Rings 106 G. 20-Membered Rings 107 H. 22-Membered Rings 107 I. 24-Membered Rings 108 J. 26-Membered Rings 108 K. 28-Membered Rings 109 L. 30-Membered Rings 109 M. Conclusions 109

4 IX. Systems Related to Annulenes 110 A. Aromatic and Antiaromatic Singly Charged Ions 110 B. Multiply Charged Ions 113 X. Annuleno-Annulenes 115 XI. Annulenes with Zero-Atom Bridges 117 References 122 Chapter 5 Bridged Annulenes 131 I. Introduction 131 II. Carbon-Bridged [10]Annulenes 131 A. Syntheses ,6-Methano[ 10] Annulene ,5-Methano[ 10]Annulene (Homoazulene) Derivatives of 7b//-Cyclopent/c,<i7Indene The Pyranene Problem 135 B. Structure and Physical Characterization ,6-Methano[ 10] Annulene 136 a. Results of Calculations 136 b. UV Spectrum 138 c. Photoelectron Spectrum 138 d. MCD Studies 138 e. NMR Spectra 139 f. X-Ray Analysis 139 g. Electron Diffraction 139 h. ESR Spectra 140 i. Dipole Moments 140 j. Valence Tautomerism ,5-Methano[ 10]Annulene (Homoazulene) Derivatives of 7b//-Cyclopent/c,?/Indene 141 C. Chemical Properties ,6-Methano[ 10]Annulene Reactions and Derivatives 141 a. Thermal Behavior 141 b. Diene Syntheses 141 c. Aromatic Substitutions 142 d. Derivatives 143 e. Metal Complexes 145 f. Derivatives with Functionalized Bridge 145 g. Formation of Benzocyclopropene and Related Compounds from 1,6-Methano[ 10] Annulene ,5-Methano[ 10]Annulene (Homoazulene) Derivatives of 7b//-Cyclopent/c,<i/Indene 149 D. Conclusions 150 III. Carbon-Bridged [12]Annulenes 150 A. Syntheses 150

5 1. Bicyclic-Bridged [ 12]Annulenes 150 a. 1,7-Methano[ 12]Annulene (146) 150 b. l,6-methano[ 12]Annulene (153) Tricyclic-Bridged [12]Annulenes Tetracyclic-Bridged [12]Annulenes 152 a. Pyracylene (161) and Derivatives 152 b. Derivatives of Dibenzo//«/,g/z/Pentalene 153 c. Derivatives of lh-cyclopent/7?,c/acenaphthene 153 d. Derivatives of Dicyclopent/«/,//yAzuIene 153 B. Structure and Physical Characterization Bicyclic-Bridged [12]Annulenes 154 a. l,7-methano[ 12]Annulene (146) 154 b. l,6-methano[ 12]Annulene (153) Tetracyclic-Bridged [12]Annulenes 155 a. Results of Calculations 155 b. Experimental Results 156 c. Conclusions 157 IV. Carbon-Bridged [14]Annulenes 157 A. Introduction 157 B. Syntheses Tricyclic-Bridged [14]Annulenes and Derivatives (Vogel's Type) 159 a. Syrc-l,6:8,13-Bismefhano[14]Annulene (188) 159 b. Anti-l,6:8,13-Bismethano[ 14]Annulene (189) 160 c. 5>n-l,6-Ethano-8,13-Methano[ 14]Annulene (190) 160 d. 15,16-Dioxo-Syz-1,6:8,13-Bismethano[ 14] Annulene (191) 160 e. 15,16-Dioxo-Anf/-1,6:8,13-Bismethano[ 14] Annulene (192) 160 f. S>n-l,6:7,12-Bisrnefhano[14]Annulene (193) Tetracyclic-Bridged [14]Annulenes and Derivatives (Vogel's Type) 161 a. 1,6:8,13-Ethanediylidene[ 14]Annulene (194) 161 b. 15,16-Methylene-1,6:8,13-Ethanediylidene[ 14] Annulene (195) 162 c. l,6:8,13-propanediylidene[14]annulene (196) 162 d. l,6:8,13-butanediylidene[14]annulene (197) 162 e. 15,16-Dialkyl-15,16-Dihydropyrenes (Boekelheide's Annulenes) and Isomers 163 f. l,3,6,8-rra«^15,16-hexamefhyldihydropyrene (265) 164 g. 7Van.s-15,16-Diethyldihydropyrene (268) 164 h. Trans-15,16-Di-n-Propyldihydropyrene (271) 164 i. Isomers of 15,16-Dimethyl-15,16-Dihydropyrene 166 j. Pyrene and Isomers 166 C. Structure and Physical Characterization Tricyclic-Bridged [14]Annulenes and Derivatives 172 a. tyn-l,6:8,13-bismethano[14]annulene (188) 172 b. A«f/-l,6:8,13-Bismethano[14]Annulene (189) 172 c. ty«-l,6-ethano-8,13-methano[ 14] Annulene (190) 172 d. 15,16-Dioxo-,S;y«- and 15,16-Dioxo-A«r/-l,6:8,13- Bismethano[ 14]Annulenes (191 and 192) 178

6 e. Syn-l,6:7,12-Bismethano[14]Annulene (193) Tetracyclic-Bridged [14]Annulenes and Derivatives 179 a. 1,6:8,13-Ethanediylidene[ 14]Annulene (194) 179 b. 15,16-Methylene-1,6:8,13-Ethanediylidene[ 14] Annulene (195) 179 c. l,6:8,13-propanediylidene[14]annulene 196) 179 d. 1,6:8,13-Butanediylidene[ 14]Annulene (197) 179 e. 15,16-Dialkyl-15,16-Dihydropyrenes (Boekelheide's Type Annulenes) 180 f. Pyrene and Isomers 182 D. Chemical Properties Vogel's Bridged [ 14]Annulenes ,16-Dialkyl-15,16-Dihydropyrenes (Boekelheide's Annulenes) 185 a. Aromatic Substitutions 185 b. Valence Tautomerism and Related Reactions 186 c. Pyrene and Isomers 189 E. Conclusions 190 Carbon-Bridged [16]Annulenes 192 A. Tricyclic-Bridged [16]Annulenes 192 B. Tetracyclic-Bridged [16]Annulenes Ethane-Bridged Systems Ethene-Bridged Systems Syntheses Structure and Physicochemical Characterization 194 C. Conclusions 195 Carbon-Bridged [18]- and [22]Annulenes 195 A. Syntheses Bridged [18]Annulenes 195 a. Syn,Syn-\,6:8,17:10,15-Trismethano[ 18] Annulene (394) 195 b. Tetracyclic Ethene-Bridged [18]Annulenes 196 c. Pentacyclic [18]Annulenes 196 d. Hexa- and Heptacyclic [18]Annulenes Bridged [22]Annulenes 198 B. Structure and Physical Characterization 198 C. Chemical Properties 199 D. Conclusions 200 Heteroatom-Containing Bridged Annulenes 202 A. Heteroatom-Bridged Annulenes Heteroatom-Bridged [10]Annulenes 202 a. Syntheses 202 b. Structure and Properties Heteroatom-Bridged [ 14]Annulenes 204 a. Syntheses 204 b. Structure and Properties 205 B. Bridged Heteroannulenes Syntheses 207

7 2. Structure and Physical Characterization Chemical Properties 211 C. Conclusions 213 VIII. Bridged Annulene Ions 214 A. Cations of l,6-methano[10]annulenes 214 B. Bridged 1 OTT-Annulene Ions 215 C. Bridged 12TT-Annulene Ions Bicyclic Systems Tricyclic Systems 216 D. Bridged 14TT-Annulene Ions Bicyclic Systems Tricyclic Systems 219 E. Bridged 16TT-Annulene Ions 220 F. Bridged 1 8TT-Annulene Ions 224 G. Bridged 20ir-Annulene Ions 225 H. Miscellaneous 226 I. Conclusions 226 References 227 Addenda 237 Index 241