INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type o f computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back o f the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 CHEMISTRY AND KINETICS OF CYCLOPROPYLCARBENES AND THEIR PRECURSORS DISSERTATION Presented in Partial Fulfillment of the Requirement for the Degree of the Doctor of Philosophy in the Graduate School of The Ohio State University by Haiyong Huang The Ohio State University 1996 Dissertation Committee: Approved by Professor Matthew S. Platz, Adviser Professor Christopher M. Hadad Professor Rajan Babu Adviser Department of Chemistry UMI Number: 9639253 UMI Microform 9639253 Copyright 1996, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT Both product studies and laser flash photolysis method have been used to study the chemistry and kinetics of cyclopropylcarbenes and their precursors. Cyclopropyldiazirines were decomposed both thermally and photochemically in various solvents in the presence of carbene quenchers, such as alkenes, alcohols and amines. With increasing concentration of carbene traps, the ring expansion products were formed in constant yield, whereas the yield of trapping products increased at the expense of solvent adduct. Thus, it is postulated that there are two intermediates produced upon decomposition of cyclopropyldiazirine: the excited state diazirine, which opens cyclopropyl ring to form cyclobutene, and cyclopropylcarbene, which decays only by intermolecular reactions with solvents or other quenchers. This mechanism is also supported by the results from laser flash photolysis experiments. A large solvent isotope effect on the carbene lifetime was observed in cyclohexane and cyclohexane-dI2, indicating that the carbene lifetime is mainly controlled by its reaction with the solvent. The decays of the cyclopropylcarbene are intermolecular rather than intramolecular. Time-resolved laser spectroscopy also provides the rate constants for reactions of cyclopropylcarbenes with solvents and pyridine. To Mom and Dad ACKNOWLEDGMENTS I wish to thank my adviser, Matthew Platz for patient guidance which made this thesis possible, and for his great kindness and friendship which made the years in his research group truly enjoyable. I’d like to thank Tetsuro Yuzawa for setting up the picosecond fast laser system and providing great insights to my questions, thank John Toscano and Jen-Lung Wang for assistance in the laser flash photolysis experiments. Special thanks to Chris Hadad for discussing with me various aspects of this thesis. I am grateful to Anna Gudmundsdottir for her advice on my thesis. I thank Anthony Czarnik for being my first mentor of graduate studies. Finally, I like to thank my family for their endless encouragement. VITA February 1, 1966 ...............................................Born-Nanjing, China 1991 ..................................................................... B. A. Chemistry Nanjing University Nanjing, China 1991-1995 ...........................................................Graduate Teaching Associate Department of chemistry The Ohio State University Columbus, Ohio 1995-present.......................................................Graduate Research Associate Department of chemistry The Ohio State University Columbus, Ohio FIELD OF STUDY Major Field: Chemistry Division: Organic Chemistry TABLE OF CONTENTS page Dedication .....................................................................................................................................iii Acknowlegement ......................................................................................................................... iv Vita.................................................................................................................................................. v List of T ables .............................................................................................................................viii List of Figures ...............................................................................................................................x Chapters: 1. Historical 1.1 Carbenes ........................................................................................................ 1 1.2 Alkylcarbenes and diazirines .......................................................................6 1.3 Cyclopropylcarbenes ................................................................................. 15 1.4 Laser photolysis and spectroscopy studies on carbenes ........................ 23 1.5 Synthetic Utilities of cyclopropylcarbenes ............................................. 27 2. Results and discussion 2.1 Introduction ...............................................................................30 2.2 3-(2-terf-Butylcyclopropyl)-3H-diazirine and (2-tert-butylcyclopropyl)carbene .............................................33 2.2.1 Synthesis of 3-(2-tert-Butylcyclopropyl)-3/7-diazirine 33 2.2.2 Product studies of 3-(2-tert-Butylcyclopropyl)- 3//-diazirine ...............................................................................36 2.2.3 LFP studies of 3-(2-tert-ButylcyclopropyI)- 3//-diazirine ...............................................................................58 2.3 Cyclopropyldiazirine and cyclopropylcarbene ......................81 2.3.1 Product studies of cyclopropyldiazirine ..................................81 2.3.2 LFP studies of cyclopropyldiazirine ....................................... 83 2.4 3-(2,2,3,3-Tetramethylcyclopropyl)-3//-diazirine ................88 2.5 Fluorescence studies of cyclopropyldiazirines ......................90 2.6 Non-nitrogenous precursors of cyclopropylcarbenes 92 2.6.1 Studies of bridged cyclopropylalkanes ...................................92 2.6.2 Studies of the Eschenmoser compound ................................. 97 3. Experimental section ........................................................................................................99 List of References .....................................................................................................................119 Appendix A Transient pyridine ylide absorption spectra of the time resolved laser flash photolysis .....................................................................124 Appendix B Miscellaneous spectra ...................................................................................... 138 LIST OF TABLES Table page 1.1 Intramolecular product distribution from decomposition of te/t-butylcarbene precursors in solution ................................................................................................. 12 1.2 Rate constants of chlorocyclopropylcarbene rearrangement and with various substrates ..................................................................................................................... 22 1.3 Lifetimes of cyclopropyl carbenes in solution at ambient temperature ................ 26 2.1 Absolute yields of products formed in the photolysis (350 nm) of diazirine 36 in CF2C1CFC12 (-25°, 0° and 25 °C) ..................................................................38 2.2 Absolute product yields obtained from photolysis of diazirine 36 in cyclohexane at ambient temperature ......................................................................... 44 2.3 Absolute product yields obtained from photolysis of diazirine 36 in pentane at ambient temperature ............................................................................................... 45 2.4 Absolute product yields obtained from photolysis of diazirine 36 in acetonitrile at ambient temperature ............................................................................ 46 2.5 Summary of k,/kTME of (2-te/t-butylcyclopropyI)carbene in several solvents.. .47 2.6 Absolute product yields from the pyrolysis of 3-(2-fcr/-butylcyclopropyl)- 3//-diazirine in CF2C1CFCI2 (100 °C) .....................................................................51 2.7 Absolute product yields obtained from the photolysis (350 nm) of diazirine 36 in pentane at ambient temperature with added cyclopentene ...........................54