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I Progress Towards the Synthesis of Plakortether B Through a Zinc-Mediated Homologation II Synthesis of Novel Hydroxy-Cyclopropyl Peptides Isosteres" (2011)

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I Progress Towards the Synthesis of Plakortether B Through a Zinc-Mediated Homologation II Synthesis of Novel Hydroxy-Cyclopropyl Peptides Isosteres University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Spring 2011 I Progress towards the synthesis of plakortether B through a zinc- mediated homologation II Synthesis of novel hydroxy-cyclopropyl peptides isosteres Ian Scott Taschner University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Taschner, Ian Scott, "I Progress towards the synthesis of plakortether B through a zinc-mediated homologation II Synthesis of novel hydroxy-cyclopropyl peptides isosteres" (2011). Doctoral Dissertations. 576. https://scholars.unh.edu/dissertation/576 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. I. PROGRESS TOWARD THE SYNTHESIS OF PLAKORTETHER B THROUGH A ZINC-MEDIATED HOMOLOGATION II. SYNTHESIS OF NOVEL HYDROXY-CYCLOPROPYL PEPTIDE ISOSTERES BY Ian Scott Taschner B.S., University of Akron, 2005 DISSERTATION Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Chemistry May, 2011 UMI Number: 3467370 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI Dissertation Publishing UMI 3467370 Copyright 2011 by ProQuest LLC. All rights reserved. This edition of the work is protected against unauthorized copying under Title 17, United States Code. uest ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Dissertation Director, Charles K. Zercher Professor of Chemistry fc uiA bhard P. Johnson Professor of Chemistry Arthur Greenberg Professor of Chemistry —^— Roy P. Planeflp Associate Professor of Chemistry ijtmdvf Donald C. Sundbqr Professor Ernes tff\<uuA 3 I zci\ Date DEDICATION This dissertation is dedicated to Michael, Deborah, and Matt Taschner. My father has always been an inspiration to my chemical career and encouraged me throughout my graduate experience. My mother has always been there for me through the highs and the lows. No matter what path I decided to take, both of my parents were always extremely supportive and loving. My brother was there to keep me in check by reminding me that life is not all about work and that a little exercise can provide relief during the most stressful times. To my family (Rico and Brendelton, too), thank you for everything that was granted to me through my chemical career. in ACKNOWLEDGEMENTS I would like to express gratitude to my graduate advisor, Professor Charles K. Zercher. His patience throughout my graduate studies has been vital to my understanding of chemistry. Starting with limited synthetic skills, Professor Zercher has molded me into an advanced chemist in the laboratory. Most importantly, he made time to help me with life situations and to overcome many of my shortcomings. For this, I thank Professor Zercher and his wonderful family. I would also like to thank all of the chemistry professors at the University of New Hampshire. Professor Planalp has provided me with organometallic knowledge, as well as motivational music every Sunday from 2-4 pm, which helped to keep my focus in lab. Professor Weisman, though intimidating at first, has taught me very valuable mechanistic skills that have carried on throughout my graduate career. Professor Greenberg and Johnson have both sparked my interest in computational chemistry, which was obsolete when I first started in the chemistry program. Professor Wong has given me insight on basic inorganic chemistry that has been useful in the understanding of the zinc-mediated homologation. Professor Wong was also available to console with at anytime, especially during my second year. I need to acknowledge my late and good friend Evan Southwick. He was an excellent chemist and friend in the beginning of my studies. Through him I have gained iv an appreciation for life and hard work required to become a successful chemist. Much love. I would like to express immense gratitude toward Dr. Thomas Jenkins and his family. Dr. Jenkins offered me an excellent opportunity to work at his company, Pharmacofore, under the guidance of Dr. Craig Husfeld. Working at Pharmacofore provided me with industrial experience and an appreciation for medicinal chemistry. Dr. Husfeld was a great mentor and most importantly a good friend. During my time at Pharmacofore, Dr. Jenkins and his family (Sherri, Alex, Max, Friar Lawrence, 8-foot, and Sister) opened their doors and provided me with a home away from home. Brian Sliter and family have always been there to support me in the toughest of times during graduate school. During the rough times, his family always invited me to their home and provided me with amazing food. For this I owe them much gratitude and appreciation. I also must show a great appreciation for the Zercher research group. Alex Jacobine, Wei-Min Lin, Karina Thorn, Matt Bixby, Jenn Mazzone, Brian Sliter, Tim Henderson, Matt Mower (CEO of Kemfinder), Pete "the beat" Moran, Carley Spencer, Deepthi Bhogadhi, Aida Ajaz, and Jared Pearl have been vital in my development as a synthetic chemist and have been great friends throughout. All of the fun and excitement I had in the lab is primarily due to these individuals. Lastly, I would like to thank the best administrative assistants ever, Cindi Rohwer and Peg Torch. v TABLE OF CONTENTS DEDICATION ACKNOWLEDGEMENTS LIST OF SCHEMES LIST OF FIGURES LIST OF TABLES LIST OF ABBREVIATIONS ABSTRACT CHAPTER I. INTRODUCTION Isosteric peptides for enzyme inhibition. Zinc Carbenoid-Mediated Homologation. Tandem Zinc Carbenoid-Mediated Homologation Reaction.. Homologation for the formation of natural products and peptide isosteres. vi II. PROGRESS TOWARD THE SYNTHESIS OF PLAKORTETHER B THROUGH A ZINC-MEDIATED HOMOLOGATION .27 Plakortether B. ....... 27 Incorporation of the Tandem Homologation-aldol. .29 Cyclization-allylation. .33 Substituted Allyl Silane. .38 III. SYNTHESIS OF NOVEL HYDROXY-CYCLOPROPYL PEPTIDE ISOSTERES 57 Peptide isosteric replacements. .57 y-Hydroxybutyrate (GHB )analogs. .63 Serendipitous discovery of bicyclic lactones.. .65 Acetoacylation via Meldrum's acid. .76 Tandem homologation-alkylation-cyclization-lactonization.. 77 Synthesis of amino acid-derived P-keto imides. .99 Determination of the major bicyclic lactone. .112 Alkylation and opening of bicyclic lactones. .116 Future Work. .118 IV. EXPERIMENTAL SECTION General experimental.. .123 (2S,3R)-Methy\ 5-hydroxy-5-methyl-2-propyltetrahydrofuran-3- vn carboxylate (72). 123 Methyl 5-allyl-tetrahydro-5-methyl-2-propylfuran- 3-carboxylate (85 and 86). .124 (25,,35,55)-Methyl5-allyl-5-methyl-2-propyltetrahydrofuran- 3-carboxylate (84). .126 (2S,3R)-tert-Buty\ 3-hydroxy-2-(2-oxopropyl)hexanoate (87). 127 3-(Trimethylsilyl)prop-2-yn-l-ol(93). .128 (Z)-2-((Dimethyl(phenyl)silyl)methylene)hexan-l-ol(95). .129 (Z)-2-((Dimethyl(phenyl)silyl)methylene)butan-l-ol(98). .130 Ethyl 3-(dimethyl(phenyl)silyl)-4-methyleneoctanoate (101). 131 Ethyl 3-(dimethyl(phenyl)silyl)-4-methylenehexanoate (100). 132 (25',3i?,55)-Methyl5-(2-(3-ethoxy-3-oxopropylidene)hexyl)- 5-methyl-2-propyltetrahydrofuran-3-carboxylate (104). 133 (5)-2-Amino-3-methylbutan-l-ol(108). .134 (5)-4-Isopropyloxazolidin-2-one (106). .135 (S)-l-(4-isopropyl-2-oxooxazolidin-3-yl)butane-l,3-dione (105). 135 (45>3-((2S;3S>5-Hydroxy-5-methyl-2-propyltetrahydrofuran- 3-carbonyl)-4-isopropyloxazolidin-2-one (110). 136 (5)-3-((25,35,55)-5-Allyl-5-methyl-2-propyltetrahydrofuran -3-carbonyl)-4-isopropyloxazolidin-2-one (109). 138 Ethyl-4-(((2i?,4S,5S)-4-((S)-4-isopropyl-2- oxooxazolidine-3-carbonyl)-2-methyl-5- viii propyltetrahydrofuran-2-yl)methyl)hex-3-enoate (111). 139 (S)-Pyrrolidin-2-ylmethanol(113). .140 (5)-2-(Hydroxymethyl)pyrrolidine-l-carbaldehyde (114). 141 (S>2-(Methoxymethyl)pyrrolidine(116). .141 L-Proline methyl ester hydrochloride salt (118 HC1). 142 L-Proline methyl ester (118). .143 (5)-Methyl l-(3-oxobutanoyl)pyrrolidine-2-carboxylate (119). 143 Methyl 1-((2i?,35,55)-5-hydroxy-5-methyl-2- propyltetrahydrofuran-3-carbonyl)pyrrolidine-2-carboxylate (120).. 144 (5)-Methyl 1-((2i?,35,55)-5-allyl-5-methyl- 2-propyltetrahydrofuran-3-carbonyl)pyrrolidine- 2-carboxylate (121). .145 (5)-Methyl-l-((2i?,35,55)-5-allyl-5- methyl-2-propyltetrahydrofuran-3-carbonyl) pyrrolidine-2-carboxylate (122). .146 (4S)-3 -(1 -Hydroxy-2-(2-oxopropyl)cyclopropyl)-4- isopropyloxazolidin-2-one (139). .147 (S>4-Isopropyl-3-((lS,3i?,5i?)-3-methyl-2-oxabicyclo [3.1.0]hexan-l-yl)oxazolidin-2-one(140) 148 Methyl 2-(2-methyl-2-((trimethylsilyl)oxy) cyclopropyl)acetate (145). .149 Methyl pivaloylacetate (154)....... 149 Methyl 2-(2-(tert-butyl)-2-((trimethylsilyl)oxy) ix cyclopropyl)acetate (156). .150 (£)-Methyl 6,6-dimethyl-5-oxohept-2-enoate (157). .151 l-Methyl2-oxabicyclo[3.1.0]hexan-3-one(159). .152 iV-Benzyl-2-(2-hydroxy-2-methylcyclopropyl)acetamide (160). 152 5-( 1-Hydroxy ethylidene)-2,2-dimethyl-1,3- dioxane-4,6-dione (162). .153 l-(2-Oxo-oxazolidin-3-yl)butane-l,3-dione (164). .154 (5>2-Amino-3-phenylpropan-l-ol(168). .154 Ethyl (5)-(l-hydroxy-3-phenylpropan-2-yl)carbamate (106a'). 155 (5)-4-Benzyloxazolidin-2-one (106a). .156 (S)-l-(4-Benzyl-2-oxooxazolidin-3-yl)butane-l,3-dione (169). 156 2-(2-Hydroxy-2-methylcyclopropyl)-./V-((i?)- l-phenylethyl)acetamide (171 and 172). .157 5-( 1 -Hydroxypropylidene)-2,2-dimethyl- l,3-Dioxane-4,6-dione(174).. .157 l-(2-Oxooxazolidin-3-yl)pentane-l,3-dione (173). 158 3-Acetyloxazolidin-2-one (177).
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