University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 8-2010 Boron and Titanium(IV) Halide Mediated Reactions Michael Patrick Quinn University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Organic Chemistry Commons Recommended Citation Quinn, Michael Patrick, "Boron and Titanium(IV) Halide Mediated Reactions. " PhD diss., University of Tennessee, 2010. https://trace.tennessee.edu/utk_graddiss/908 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Michael Patrick Quinn entitled "Boron and Titanium(IV) Halide Mediated Reactions." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Chemistry. George W. Kabalka, Major Professor We have read this dissertation and recommend its acceptance: Shane Foister, Ziling (Ben) Xue, Paul Dalhaimer Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a dissertation written by Michael Patrick Quinn entitled ―Boron and Titanium(IV) Halide Mediated Reactions.‖ I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Chemistry. George W. Kabalka, Major Professor We have read this dissertation and recommend its acceptance: __Shane Foister __Ziling (Ben) Xue __Paul Dalhaimer Accepted for the Council: _ Carolyn R. Hodges _ Vice Provost and Dean of the Graduate School (Original signatures are on file with official student records.) BORON AND TITANIUM(IV) HALIDE MEDIATED REACTIONS A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Michael Patrick Quinn August 2010 DEDICATION To my best friend and wife, Amber, Thank you for all the support during this process, You have been a tremendous source of strength and advice, I could not have done this without your help. ii ACKNOWLEDGMENTS I would first like to acknowledge my advisor, Dr. George W. Kabalka. Thank you for all the support you have shown me over the past several years. Working with you has been a privilege and there are not enough words to express my gratitude. I would also like to acknowledge Dr. Min-Liang Yao. Thank you for your insight and help over the past years, again, there are not enough words to express my gratitude. I would also like to thank my committee members; Dr. Shane Foister, Dr. Ziling (Ben) Xue, and Dr. Paul Dalhaimer. Great teachers do more than convey subject matter; they inspire us with enthusiasm, motivate with optimism, offer true support when needed, and provide us with the right questions. Therefore, I would like to express my gratitude to the Faculty of the Chemistry Department at the University of Tennessee. It has been a pleasure to work and learn with you. I would also like to specifically thank Dr. Ron Magid and Dr. George Schweitzer who were not only instrumental in developing my interest in pursuing a career in chemistry but provided the recommendations to do so. I would also like to express my sincerest thanks to the Kabalka Group. There is not enough paper nor time for me to truly express my how truly great it has been, thank you Kelly Hall, Li Yong, Travis Quick, Adam Pippin, Coltuclu Vitali, Thomas Moore, and David Blevins. I would also like to thank Brad Miller and Josh Abbott for all their help in making ACGS a better organization and for all the fun we had while doing it. To all my other friends who made this one of the best experiences of my life thus far, thank you. Finally, I am deeply grateful to my wife and family. Without your support, this goal might not have been realized. I would also like to express my sincerest gratitude to God. Thank you. iii ABSTRACT This dissertation summarizes research efforts focused on the use of boron and transition metal halides to form new carbon-carbon and carbon-halide bonds. The boron halide mediated alkyne-aldehyde coupling reaction to generate 1,3,5-triaryl-1,5-dihalo-1,4-dienes was reinvestigated in an attempt to explain the stereochemistry observed during changing of both the mode of addition and the reaction temperature. Either (Z,Z)-1,4-dienes or (Z,E)-1,4-dienes can be the predominant product depending on reaction conditions used. This mechanistic investigation also led to the discovery of several novel reactions. These include the stereoselective preparation of (Z)-3-chloroallylic ethers from the reaction of alkenylboron dichlorides with aryl aldehydes in the presence of an amine; the titanium(IV) halide coupling of alkoxides and alkynes; the haloallylation of aryl aldehydes with boron trihalide using different allylmetals; and the base induced elimination of the haloallylated products to form 1,3-dienes. The results of these studies strongly imply a cationic mechanism. The new reactions described herein can be characterized as atom-efficient, environmentally friendly, and capable of generating the desired products in good to excellent yields. iv TABLE OF CONTENTS Chapter 1. Lewis Acids in Organic Synthesis ........................................................................... 1 1.1 Scope of this Dissertation ....................................................................................................1 1.1.1 Historical Aspects of Boron and Transition Metal Halides in Organic Synthesis ...... 1 1.1.2 Reactions of Boron Trihalides in Organic Chemistry ................................................. 2 1.1.3 Reactions of Titanium(IV) Halides in Organic Chemistry ......................................... 5 1.2 Alcohol Functional Group Conversion ................................................................................7 1.3 Synthesis of Alkenyl Halides and Alkenylation of Carbonyl Groups .................................7 1.4 Allylation of Carbonyl Compounds ...................................................................................10 1.5 Boron Trihalide Haloboration of Alkynes .........................................................................11 1.6 Statement of Problem ........................................................................................................13 Chapter 2. Reaction Pathways Involved in Boron Trichloride Mediated Alkyne-Aldehyde Coupling under Varying Reaction Conditions ..................................................... 14 2.1 Introduction ........................................................................................................................14 2.2 Results and Discussion ......................................................................................................16 2.3 Conclusions ........................................................................................................................21 2.4 Experimental ......................................................................................................................22 2.4.1 General Methods ....................................................................................................... 22 2.4.2 Typical Reaction Procedure ...................................................................................... 23 2.4.3 Characterization of Compound ................................................................................. 23 Chapter 3. Stereoselective Preparation of (Z)-3-Chloroallylic Ethers: The reaction of Alkenylboron Dichlorides with Aryl Aldehydes in the Presence of Amine ....... 24 3.1 Introduction ........................................................................................................................24 3.2 Results and Discussion ......................................................................................................25 3.2.1 Generation of (Z)-3-Chloroallylic Alcohols ............................................................. 25 3.2.2 Allyltrimethysilane ................................................................................................... 28 3.2.3 (Z)-3-Chloroallylic Ethers ......................................................................................... 29 3.3 Conclusions ........................................................................................................................31 3.4 Experimental ......................................................................................................................31 3.4.1 General Methods ....................................................................................................... 31 3.4.2 Typical Reaction Procedure for (Z)-3-Chloroallylic Alcohol ................................... 32 3.4.3 Typical Reaction Procedure for (Z)-3-Chloroallylic Ether ....................................... 33 3.4.4 Characterization of Compounds ............................................................................... 33 v Chapter 4. Titanium(IV) Halide Mediated