Experimental and Computational Studies of Theoretically Significiant Alkenes Richard O
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Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1985 Experimental and computational studies of theoretically significiant alkenes Richard O. Angus Jr. Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Organic Chemistry Commons Recommended Citation Angus, Richard O. Jr., "Experimental and computational studies of theoretically significiant alkenes " (1985). Retrospective Theses and Dissertations. 12042. https://lib.dr.iastate.edu/rtd/12042 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 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Un International SOON.Zeeb Road Ann Arbor, Ml 48106 8524632 Angus, Richard 0., Jr. EXPERIMENTAL AND COMPUTATIONAL STUDIES OF THEORETICALLY SIGNIFICANT ALKENES Iowa State University PH.D. 1985 University Microfilms IntGrn&tlOnâl SOON. ZeebRoad, Ann Arbor,Ml48106 PLEASE NOTE: In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages 2. Colored illustrations, paper or print 3. Photographs with dark background 4. Illustrations are poor copy 5. Pages with black marks, not original copy 6. Print shows through as there is text on both sides of page 7. Indistinct, broken or small print on several pages 8. Print exceeds margin requirements 9. Tightly bound copy with print lost in spine 10. Computer printout pages with indistinct print 11. Page(s) . lacking when material received, and not available from school or author. 12. Page(s) seem to be missing in numbering only as text follows. 13. Two pages numbered Text follows. 14. Curling and wrinkled pages 15. Dissertation contains pages with print at a slant, filmed as received . 16. Other University Microfilms International Experimental and computational studies of theoretically significant alkenes by Richard 0. Angus, Jr. A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Chemistry Major; Organic Chemistry Approved: Members of the Committee: Signature was redacted for privacy. Signature was redacted for privacy. In Charge of MaJjôr Work Signature was redacted for privacy. Signature was redacted for privacy. For the Graduate College Iowa State University Ames, Iowa 1985 ii TABLE OF CONTENTS Page LIST OF ABBREVIATIONS ix Organic Functional Groups ix Reagents and Solvents ix DEDICATION x ABSTRACT xii GENERAL INTRODUCTION 1 PART I. COLUMNAR HOMOCONJUGATION 2 Nonconjugated Interaction of ir Orbital s 2 Introduction to Columnenes 13 Theoretical MO Analyses of Columnar Homoconjugation 18 Conclusions 31 Synthetic Strategy Toward Columnenes 33b Butatriene synthetic equivalent 34 Butatriene synthetic equivalent approach to columnenes 40 Bis-allyl synthetic equivalent approach to columnenes 47 Conclusions 68 Future Synthetic Work 70 Experimental Section 77 General method 77 Experimental details 78 References Cited 110 PART II. STRUCTURAL LIMITATIONS OF STRAINED CYCLIC OLEFINS 117 Introduction to Cyclic Aliénés 117 1,2-Cyclohexadiene 121 Large ring cyclic aliénés 124 Four- and five-membered cyclic aliénés 125 111 Bicyclo[3.2.1]octatr1enes 126 Heterocyclic aliénés 128 Theoretical Investigation of the Structural Limitations of Cyclic Aliénés 130 Aliéné bending potential 131 MNDO calculations for cyclic aliénés 134 Ab initio calculations for 1,2-cyclopenta- and 1,2-cyclohexadiene 139 Conclusions 143 Introduction to Cyclic Butatrlenes 144 Theoretical Calculations 147 Butatriene bending potential 147 Cyclic butatriene calculations 149 Synthesis of 1,2,3-Cyclononatriene 154 Conclusions 159 Experimental Section 150 Experimental details 160 Introduction to trans Cyclic Olefins 163 MNDO Study of trans-Cyclic Olefins 170 Conclusions 175 References Cited 176 GENERAL CONCLUSION 181 ACKNOWLEDGMENTS 182 iv LIST OF FIGURES Page For Part I: Figure 1 Simple MO representation of homoconjugative 3 splitting of u orbitals Figure 2 Simple MO representation of hyperconjugative 4 a-if interaction Figure 3 Inference of w MO level ordering in norbornadiene 6 using a preturbation approach Figure 4 Effect of dihedral angle, ui, upon for 8 1,4-cyclohexadlenes Figure 5 w MO energies of norbornadienylogues series as 8 a function of dihedral angle w Figure 6 Change in energy of u, ir and HO-o-MO of 9 as a 10 function of the distance between ir bonds Figure 7 Orbital topology for columnar homoconjugation 14 of three ir bonds Figure 8 Huckel molecular orbital energy levels 19 calculated for tri-, tetra-, and pentacolumnene Figure 9 Extended Huckel molecular orbital energy levels 20 calculated for tri-, tetra-, and pentacolumnene Figure 10 Optimized geometry for tricolumnene (17) 24 Figure 11 Optimized geometry for tetracoTumnene (18) 25 Figure 12 Optimized geometry for pentacolumnene (19) 26 Figure 13 tt Molecular orbital energies for 17-19 29 Figure 14 HOMO and LUMO orbital topology predicted for 33a tetracolumnene Figure 15 300 MHz NMR (COCU) analysis of the reaction of 63 ambiphile 98 with time Figure 16 300 MHz ^H NMR (benzene-dg) analysis of the reaction 64 of ambiphile 98 with time Figure 17 NMR spectral assignments for closed dimer 101 55 For Part II: Figure 1 Independent bending and twisting of aliénés 118 Figure 2 Electronic configurations for bent planar aliéné 120 Figure 3 State correlation for racemization in C2 aliéné 130 Figure 4 vs aliéné bending angle, o 132 Figure 5 Bent aliéné, 34(a), viewed along the C=C=C plane 133 Figure 6 ORTEP representations of MNDO predicted geometries 136 for cyclic aliénés Figure 7 MNDO optimized geometry for bicyclo[3.2.1]octa-2,3,6- 138 triene, 20 and its diradical 21-^D Figure 8 ST0-3G optimized geometries for chiral 1,2-cyclo 140 hexadiene 1(6) and the geometry 1(6)-^D corresponding to its barrier to thermal racemization Figure 9 ST0-3G optimized geometries for chiral 1,2-cyclo 141 pentadiene 1(5) and the geometry 1(5)-^0 corresponding to its barrier to thermal racemization Figure 10 Butatriene bending potential 148 Figure 11 MNDO optimized geometries for cyclic butatrienes 150 Figure 12 NMR spectrum of complexed 1,2,3-cyclononatriene 155 Figure 13 ORTEP representation of complex 43 158 Figure 14 ORTEP stereoview of complex 43 159 Figure 15 ORTEP representations of trans cyclic olefins 172 vi LIST OF TABLES Page For Part I: Table 1 Cartesian coordinates for symmetry atoms (Bohrs) 22 Table 2 Optimized geometric parameters for columnenes 23 Table 3 Total energies for columnar structures (hartrees) 28 Table 4 Columnene trends observed from 3-21G||ST0-3G 30 calculations Table 5 Lewis acid catalized Diels-Alder cyclodemerization 57 attempts For Part II; Table 1 MNDO results for cyclic aliénés 137 Table 2 Racemization barriers predicted for 1,2-cyclopentadiene 142 Table 3 Racemization barriers predicted for 1,2-cyclohexadiene 143 Table 4 Selected MNDO geometrical parameters for cyclic 151 butatrienes Table 5 Energies (aH^) for cyclic butatrienes 152 Table 6 Selected geometric parameters of trans-cyclic olefins 173 Table 7 MNDO heats of formation of trans-cyclic olefins 174 vii LIST OF SCHEMES Page For Part I: Scheme 1 Potential Diels-Alder routes to columnenes 33b Scheme 2 Conceptual preparation of columnene