DOCSLIB.ORG

Iron-Catalyzed Amino-Oxygenation and Aminofluorination of Olefins

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Iron-Catalyzed Amino-Oxygenation and Aminofluorination of Olefins Georgia State University ScholarWorks @ Georgia State University Chemistry Theses Department of Chemistry 8-11-2015 Iron-Catalyzed Amino-Oxygenation and Aminofluorination of Olefins Jeffrey Sears [email protected] Follow this and additional works at: https://scholarworks.gsu.edu/chemistry_theses Recommended Citation Sears, Jeffrey, "Iron-Catalyzed Amino-Oxygenation and Aminofluorination of Olefins." Thesis, Georgia State University, 2015. https://scholarworks.gsu.edu/chemistry_theses/77 This Thesis is brought to you for free and open access by the Department of Chemistry at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Chemistry Theses by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. IRON-CATALYZED AMINO-OXYGENATION AND AMINOFLUORINATION OF OLEFINS by JEFFREY D. SEARS Under the Direction of Hao Xu, PhD ABSTRACT The first chapter of the thesis describes an iron(II)-catalyzed intermolecular amino- oxygenation of alkenes. This amino-oxygenation method is found to be compatible with a broad range of synthetically valuable alkenes and affords the corresponding 1,2-amino alcohols with excellent regio- and diastereoselectivity. Additionally, practical synthetic procedures for the amino-oxygenation of styrene, a fully functionalized glycal, and indene are described. The second chapter of the thesis describes a regioselective and diastereoselective iron(II)-catalyzed intermolecular aminofluorination of alkenes using nucleophilic fluorinating reagents. This method affords new vicinal amino fluorides that were previously difficult to prepare. In both the amino-oxygenation and aminofluorination reactions, bench-stable hydroxylamine derivatives functioned as both the oxidant and amination reagents. Preliminary mechanistic studies suggested that an iron-nitrenoid is a possible reactive intermediate on both reaction pathways. These new difunctionalization strategies represent efficient alternatives to current amino- oxygenation and aminofluorination methods. INDEX WORDS: selective catalysis, iron, olefin, oxidation, amination, fluorination IRON-CATALYZED AMINO-OXYGENATION AND AMINOFLUORINATION OF OLEFINS by JEFFREY D. SEARS A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Masters of Organic Chemistry in the College of Arts and Sciences Georgia State University 2015 Copyright by Jeffrey D. Sears 2015 IRON-CATALYZED AMINO-OXYGENATION AND AMINOFLUORINATION OF OLEFINS by JEFFREY D. SEARS Committee Chair: Hao Xu Committee: Hao Xu Alfons Baumstark Ivaylo Ivanov Electronic Version Approved: Office of Graduate Studies College of Arts and Sciences Georgia State University July 2015 iv DEDICATION To my parents Carolyn and Michael Sears. v ACKNOWLEDGEMENTS I would like to thank Professor Hao Xu. I probably never would have realized my interest in chemical research if it were not for a random hallway conversation about battery technology and catalysis. I will always be grateful for the guidance and support he has provided throughout my undergraduate and graduate studies. It has been a privilege to be a part of his research group. I would like to thank each member of the Xu group, past and present, for their help. I have had the distinct pleasure to become close friends with many of them. I am especially grateful to Dr. Dengfu Lu and Chengliang Zhu for their mentorship. I will always be appreciative of their patience. Additionally, I thank Dr. Dengfu Lu, Chengliang Zhu and Yongan Yuan for proofreading this thesis. I would also like to thank Professor Alfons Baumstark for his guidance during my graduate studies. His attention to detail and enthusiasm for education have left a lasting impression on me. Lastly, I would like to thank all members of my committee, Professors Ivaylo Ivanov, Hao Xu, and Alfons Baumstark for their review of this thesis. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................. v LIST OF TABLES ......................................................................................................... viii LIST OF FIGURES ......................................................................................................... ix 1 INTRODUCTION ...................................................................................................... 1 1.1 Fe(II)-Catalyzed Intermolecular Amino-Oxygenation of Alkenes ................. 1 1.2 Fe(II)-Catalyzed Intermolecular Aminofluorination of Alkenes .................... 6 2 EXPERIMENT ......................................................................................................... 10 2.1 General Information ......................................................................................... 10 2.1.1 General Procedures....................................................................................... 10 2.1.2 Materials ........................................................................................................ 10 2.1.3 Instrumentation ............................................................................................. 10 2.1.4 Other Abbreviation Used .............................................................................. 11 2.2 Iron(II)-Catalyzed Alkene Amino-Oxygenation ............................................ 11 2.2.1 Synthesis of Acyloxyl Carbamates (2a and 2b) ............................................ 11 2.2.2 Synthesis of Nitrogen-based Tri-dentate Ligands ......................................... 13 2.2.3 Procedure for the Iron-Catalyzed Gram-Scale Glycal Amino-Oxygenation .... 16 2.3 Iron(II)-Catalyzed Alkene Aminofluorination ............................................... 20 2.3.1 Synthesis of Acyloxyl Carbamate 2d ............................................................ 20 2.3.2 General Procedure A for the Iron-Catalyzed Alkene Aminofluorination .. 21 vii 2.3.3 General Procedure B for the Iron-Catalyzed Alkene Aminofluorination .. 22 3 RESULTS AND DISCUSSION ............................................................................... 24 3.1 Fe(II)-Catalyzed Amino-Oxygenation of Alkenes .......................................... 24 3.2 Fe(II)-Catalyzed Aminofluorination of Alkenes ............................................ 35 4 CONCLUSIONS ....................................................................................................... 43 APPENDIX ...................................................................................................................... 45 4.1 Aminofluorination (AF) NMR Spectra (1H, 13C, and 19F) ............................. 45 REFERENCES ................................................................................................................ 48 viii LIST OF TABLES Table 1: Iron-Ligand Complex and Acyloxyl Carbamate Relationship for the Amino- Oxygenation of Styrene ................................................................................................................ 25 Table 2: Iron-L1 Catalyzed Amino-Oxygenation Substrate Scope .................................. 28 Table 3: Iron-L2 Catalyzed Amino-Oxygenation Substrate Scope .................................. 34 Table 4: Iron-L1 Catalyzed Aminofluorination Substrate Scope ..................................... 40 ix LIST OF FIGURES Figure 1: Osmium-Catalyzed Sharpless Olefin Aminohydroxylation1l .............................. 2 Figure 2: A Selected Example of Palladium-Catalyzed Aminoacetoxylation of Alkenes1h2 Figure 3: A Selected Example of Palladium-Catalyzed Olefin Amino-Oxygenation for the Synthesis of Tetrahydrofurans1a ...................................................................................................... 3 Figure 4: Copper-Catalyzed Asymmetric Intramolecular Amino-Oxygenation of Alkenes1i ......................................................................................................................................... 3 Figure 5: Copper(II)-Catalyzed Amino-Oxygenation of Alkenes with Sulfonyl Oxaziridines1j .................................................................................................................................. 4 Figure 6: Iron-Catalyzed Amino-Oxygenation of Alkenes with Sulfonyl Oxaziridines1k . 5 Figure 7: Iron(II)-Catalyzed Intramolecular Amino-Oxygenation of Alkenes with Functionalized Hydroxylamines6 .................................................................................................... 6 Figure 8: Representative Pharmaceuticals with Fluorines7 ................................................ 6 Figure 9: Palladium-Catalyzed Intramolecular Aminofluorination of Alkenes9 ................ 7 Figure 10: Palladium-Catalyzed Intermolecular Aminofluorination of Styrenes Using NFSI10 ............................................................................................................................................. 7 Figure 11: Silver-Catalyzed Radical Intramolecular Aminofluorination of Alkenes in Aqueous Media11 ............................................................................................................................ 8 Figure 12: Enantioselective Fluoroamination: 1,4-Addition to Conjugated Dienes Using Anionic Phase-Transfer Catalysis12 ................................................................................................ 8 Figure 13: Iron(II)-Catalyzed Intramolecular Aminofluorination of Alkenes4c ................. 9 Figure 14: Synthesis of Acyloxyl Carbamats 2a-c ..........................................................
Load more

Recommended publications
  • Curriculum Vitae Kazimer Lennon Skubi
    CURRICULUM VITAE KAZIMER LENNON SKUBI Skidmore College Department of Chemistry Office: (518) 580-5147 815 North Broadway Email: [email protected] Saratoga Springs, NY 12866 ORCID: 0000-0002-9689-1842 EDUCATION AND TRAINING Yale University 2017–2020 NIH F32 Postdoctoral Fellow (Advisor: Patrick Holland) University of Wisconsin–Madison 2011–2017 Ph.D. in Chemistry (Advisor: Tehshik Yoon) Thesis Title: “New Strategies for Catalytic Stereocontrol in Photochemical Synthesis” Carleton College 2007–2011 B.A. in Chemistry, summa cum laude ACS-Certified Degree, Distinction in Major, Distinction in Senior Integrative Exercise PROFESSIONAL EXPERIENCE Visiting Assistant Professor of Chemistry, Skidmore College, Saratoga Springs, NY 2020–present NIH F32 Postdoctoral Fellow, Yale University, New Haven, CT 2018–2020 Postdoctoral Associate, Yale University, New Haven, CT 2017–2018 Graduate Student Research Assistant, University of Wisconsin–Madison, Madison, WI 2015–2017 Graduate Student Teaching Assistant, University of Wisconsin–Madison, Madison, WI 2011–2015 TEACHING EXPERIENCE Skidmore College CH 125: Principles of Chemistry + Lab Fall 2020 University of Wisconsin–Madison (Teaching Assistant) CHEM 344: Organic Chemistry Laboratory Fall 2011, Spring 2012 CHEM 345: Organic Chemistry II Spring 2014 CHEM 346: Intermediate Organic Chemistry Laboratory Fall 2013, Fall 2014, Fall 2015 CHEM 636: Introduction to NMR Fall 2012, Spring 2013 CHEM 637: Advanced Methods in NMR Summer 2013 Carleton College (Teaching Assistant) CHEM 123: Introductory Chemistry Fall 2009 CHEM 233: Organic Chemistry I Winter 2010, Fall 2010, Winter 2011 CHEM 234: Organic Chemistry II Spring 2010, Spring 2011 MENTORING EXPERIENCE Graduate Student Mentor, Holland Research Group 2017–2020 Fundamentals of Inclusive Teaching (Yale Center for Teaching and Learning) Fall 2018 Teaching in Science and Engineering: The College Classroom (UW–Madison Dept.
    [Show full text]
  • Read Laura's Thesis Chapter
    Communicating Research to the General Public At the March 5, 2010 UW-Madison Chemistry Department Colloquium, Prof. Bassam Z. Shakhashiri, the director of the Wisconsin Initiative for Science Literacy (WISL), encouraged all UW-Madison chemistry Ph.D. candidates to include a chapter in their Ph.D. thesis communicating their research to non-specialists. The goal is to explain the candidate’s scholarly research and its significance to a wider audience that includes family members, friends, civic groups, newspaper reporters, program officers at appropriate funding agencies, state legislators, and mem- bers of the U.S. Congress. Over 20 Ph.D. degree recipients have successfully completed their theses and included such a chapter. WISL encourages the inclusion of such chapters in all Ph.D. theses everywhere through the cooperation of Ph.D. candidates and their mentors. WISL is now offering additional awards of $250 for UW-Madison chemistry Ph.D. candidates. The dual mission of the Wisconsin Initiative for Science Literacy is to promote literacy in science, mathematics and technology among the general public and to attract future generations to careers in research, teaching and public service. UW-Madison Department of Chemistry 1101 University Avenue Madison, WI 53706-1396 Contact: Prof. Bassam Z. Shakhashiri [email protected] www.scifun.org May 2014 Controlling the Chemistry of Photogenerated Radicals with Lewis and Brønsted Acid Co-Catalysts By Laura Ruiz Espelt A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemistry) at the UNIVERSITY OF WISCONSIN!MADISON 2014 Date of final oral examination: 08/06/2014 The dissertation is approved by the following members of the Final Oral Committee: Tehshik Yoon, Professor, Chemistry Clark Landis, Professor, Chemistry Shannon Stahl, Professor, Chemistry Jennifer Schomaker.
    [Show full text]
  • Badger Chemist the Newsletter of the Department of Chemistry at the University of Wisconsin-Madison
    Badger Chemist The Newsletter of the Department of Chemistry at the University of Wisconsin-Madison Established 1953, No. 57, 2014 BADGER CHEMIST Ten People, Ten Stories Ever since joining the faculty at the University of Wisconsin-Madison 25 years ago, one of the things that has most impressed me is the astounding variety of science, classes, and other activities that happen in our department each day. If you were to explore the Chemistry Building and talk to 10 people, each one might easily tell you a different story about an exciting new research project, a meaningful class experience, a poster or publication in progress, or a new program for students or the community. With this issue of the Badger CONTENTS Chemist, we aim to give you a taste of this great diversity of teaching, research, and outreach. New Badger Chemists .................................... 2 Whether you have fond memories of learning the ins and outs Alumni News ................................................... 4 of the department’s chemical instruments (page 15), you want to Chemistry News .............................................. 5 find out the latest update on the Chemistry Building Project (page Awards and Honors ....................................... 11 Features ......................................................... 15 6), you’re curious what chemistry majors are learning in the lab Shakhashiri ACS Presidency Reflections ...... 19 these days (page 17), or you want to meet our newest professor New Faculty Profile ......................................
    [Show full text]
  • 42 National Organic Chemistry Symposium Table of Contents
    42nd National Organic Chemistry Symposium Princeton University Princeton, New Jersey June 5 – 9, 2011 Table of Contents Welcome……………………………………………………………………………….......... 2 Sponsors / Exhibitors…..……………………………………………………………........... 3 DOC Committee Membership / Symposium Organizers………………………….......... 5 Symposium Program (Schedule)……...…………………………………………….......... 9 The Roger Adams Award…………………………………………………………….......... 14 Plenary Speakers………………………………………………………………………........ 15 Lecture Abstracts..…………………………………………………………………….......... 19 DOC Graduate Fellowships……………………………………………………………....... 47 Poster Titles…………………………...……………………………………………….......... 51 General Information..………………………………………………………………….......... 93 Attendees………………………………..……………………………………………........... 101 Notes………..………………………………………………………………………….......... 117 (Cover Photo by Chris Lillja for Princeton University Facilities. Copyright 2010 by the Trustees of Princeton University.) -------42nd National Organic Chemistry Symposium 2011 • Princeton University Welcome to Princeton University On behalf of the Executive Committee of the Division of Organic Chemistry of the American Chemical Society and the Department of Chemistry at Princeton University, we welcome you to the 42nd National Organic Chemistry Symposium. The goal of this biennial event is to present a distinguished roster of speakers that represents the current status of the field of organic chemistry, in terms of breadth and creative advances. The first symposium was held in Rochester NY, in December 1925, under the auspices of
    [Show full text]
  • Badger Chemist
    Est. 1953. NO. 49 2005 Badger Chemist THE NEWSLETTER OF THE UNIVERSITY OF WISCONSIN - MADISON CHEMISTRY DEPARTMENT THE NEWSLETTER OF THE UNIVERSITY OF WISCONSIN –MADISON C H E M I S T R Y DEPARTMENT CONTENTS From the Chair . 1 Current Chemistry News . 2 Our Awards . 9 New Badger Chemists. 11 Other Notable News. 13 Institute for Chemical Education . 16 The ACS Chemluminary Celebration. 18 Wisconsin Initiative for Science Literacy. 20 Journal of Chemical Education. 23 This ‘n’ That . 25 Chemistry Department Support . 27 Donors to Department Funds. 31 In Memoriam. 34 2005 BADGER CHEMIST Matthew Sanders Editor Est. 1953 NO. 49 Designed by the Instructional Media Development Center School of Education, University of Wisconsin–Madison Linda Endlich 2005 Art Direction Katie Drapp & Candice Heberer Production Assistance From the Chair January 2006 Dear Badger Chemists, I am now well into my second year as Chair of the Chemistry Department. I am grateful for the strong support the Department has received from the College of Letters and Science, and for the support I have received from my colleagues in the Department. As a result my eighteen months as Chair have been rewarding (and stimulating and busy!). The Badger Chemist, under the exceptional editorship of our Executive Director, Matt Sanders, is a wonderful vehicle for communicating our activities to alumni and friends. This issue of the Badger Chemist highlights our activities of the 2004-05 academic year, and indeed, there were many! On the teaching front, we continue to make significant efforts to excel. These efforts include training TAs in the fall, mentoring new faculty, and securing federal funding for research in education.
    [Show full text]
  • Camille Dreyfus Teacher-Scholar Awards Program
    Camille Dreyfus Teacher-Scholar Awards Program Institution Awarde Project e 2020 Arizona State University Gary F. Moore Bioinspired Materials for Green Chemistry Brown University Ou Chen From Nanocrystals to Macromaterials: Bridging the Divide Dartmouth College Katherine Mirica Molecular Engineering of Multifunctional Materials for Chemical Sensing and Microelectronics Duke University Emily Derbyshire Chemical Approaches to Understand Infectious Agents Harvard University Christina Woo Chemical Control of Cellular Signaling Massachusetts Institute of Gabriela Schlau-Cohen Elucidating Structural and Energetic Dynamics of Membrane Technology Proteins The Ohio State University L. Robert Baker Visualizing Charge and Spin Dynamics at Interfaces The University of Chicago Suriyanarayanan Vaikuntanathan Controlling Organization, Self-assembly, and Dynamics in Complex Non-equilibrium Systems The University of North Carolina Frank Leibfarth Modern Approaches to Functional and Sustainable Thermoplastics at Chapel Hill University of California, Berkeley Evan Miller Chemical Indicators to Visualize Cellular Physiology University of California, Los Alexander Spokoyny Hybrid Materials and Reagents Featuring Boron-Rich Clusters Angeles University of Michigan Alison Narayan Biocatalytic Reactions for Selective, Sustainable Synthesis University of Rochester Ellen Matson Multimetallic Metal Oxide Clusters for Electrochemical Energy Storage and the Production of Chemical Fuels Vanderbilt University Steven Townsend Chemical Approaches for Trojan-Horse Microbicidal
    [Show full text]
  • Tehshik Yoon ([email protected]) 5317 Chemistry Office Hours: Mondays, 2:00–4:00Pm
    CHEMISTRY 547 – FALL 2016 MWF 12:05–12:55pm, Room 1315 Chemistry Instructor: Tehshik Yoon ([email protected]) 5317 Chemistry Office Hours: Mondays, 2:00–4:00pm Course Description: Chem 547 is course in advanced organic chemistry appropriate for upper- level undergraduates and beginning graduate students. The learning objectives in this course are: (1) to familiarize you with the conceptual and mechanistic underpinnings of modern organic synthesis, (2) to advance your understanding of practical organic synthesis beyond the rudimentary level taught in introductory sophomore-level organic chemistry, and (3) to introduce you to the central issues in modern synthetic research. Textbook: While there is no formal textbook for this course, I will suggest readings from Louden, the textbook used for Chem 343 and 345 at UW–Madison. Other materials will be handed out in class and posted to Learn@UW. Additional Reading: • Carey and Sundberg, Advanced Organic Chemistry, Parts A and B. These have been the go-to textbooks for third-semester organic chemistry for a long time. They are, however, somewhat out of date. • J. March Advanced Organic Chemistry, Reactions, Mechanisms and Structure. An encyclopedic listing of organic reactions, along with general chapters covering bonding, stereochemistry, reactive intermediates, and photochemistry. • K. C. Nicolaou, Classics in Total Synthesis. Excellent narrative coverage of 36 landmark syntheses with an analysis of the synthetic advances that made each possible. There are two more volumes, but I find this one the most useful for learning total synthesis. Exams: Three midterm exams (100 pts each) covering each of three main units: Exam 1: October 14(MO theory and pericyclic reactions) Exam 2: November 11 (Carbonyl chemistry) Exam 3: December 14 (Redox chemistry and transition metal catalysis) Homework: Problem sets will be assigned weekly.
    [Show full text]
  • Thieme-Chemistry.Com
    SynformPeople, Trends and Views in Chemical Synthesis 2017/03 Borane-Catalyzed Ring-Opening and Ring- Closing Cascades of Furans Leading to Silicon- Functionalized Synthetic Intermediates Highlighted article by C. K. Hazra, N. Gandhamsetty, S. Park, S. Chang Contact Your opinion about Synform is welcome, please correspond if you like: [email protected] Thieme A37 Synform Dear Readers, Don’t you have the feeling that our job of publishing In this issue research articles is becoming increasingly difficult, while editors and reviewers – regardless of the impact factor SYNTHESIS Highlight of the journal – have increasingly and unreasonably high A General and Robust Method for the Preparation of (E)- and (Z)-Stereodefined Fully Substituted Enol expectations and demands? Well, I do. Medicinal and Tosylates: Promising Cross-Coupling Partners .........A38 biological chemistry is an area where this issue is becom- ing particularly serious. Trying to publish the results of Literature Coverage exploratory pilot work without having in vivo data (on Enantioselective Photochemistry through Lewis Acid Catalyzed Triplet Energy Transfer ..........................A44 some sort of animal model) is getting increasingly chal- lenging even in journals that only a decade ago would let Literature Coverage authors get away with just a handful of in vitro tests or not Borane-Catalyzed Ring-Opening and Ring-Closing even that. But authors in other areas – such as synthetic Cascades of Furans Leading to Silicon-Functionalized Synthetic Intermediates .....................................A48 methodology – are certainly not in a better situation, with editors and reviewers having all sorts of often unreason- Young Career Focus able demands and requests to perform additional experi- Young Career Focus: Dr.
    [Show full text]
  • Design and Development of New Enantioselective Catalytic Reactions and Progress Towards the Total Synthesis of Callipeltoside A
    Design and Development of New Enantioselective Catalytic Reactions and Progress towards the Total Synthesis of Callipeltoside A Thesis by John Jacob Moely Wiener In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2004 (Defended 20 January 2004) ii „ 2004 John Jacob Moely Wiener All Rights Reserved iii This thesis is dedicated to David, Mommy, and Da with more love than I can express iv Acknowledgements The MacMillan group has, since its inception, adhered to a level of excellence that can be as powerfully exciting as depressingly backbreaking in its intensity. These standards have been set by my adviser, David MacMillan, and I must thank Dave for being a model to me of the scientific method, of the necessity to strive for perfection in research. But more, Dave holds dear the pursuit of new understandings, and this passion is infused deep within his research group. I cannot thank him enough for helping me both to harness the elements of that drive that are within myself and to use that drive to perform as I have during these five and a half years. My interest in chemistry was first given structure by Professor David Evans, with whom it was my incredible privilege to engage in research during my final two years of college at Harvard. The skills and knowledge I gained from Dave and his powerful group of researchers gave me supreme confidence as I headed to tackle the challenges of graduate school, and his continued absolute support has been invaluable as I have made my way through school and towards the workplace.
    [Show full text]
  • Novel Variants of the Zwitterionic Claisen Rearrangement and the Total Synthesis of Erythronolide B
    Novel Variants of the Zwitterionic Claisen Rearrangement and the Total Synthesis of Erythronolide B Thesis by Vy Maria Dong In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Chemistry California Institute of Technology Pasadena, California 2004 (Defended October 31, 2003) ii © 2004 Vy Maria Dong All Rights Reserved iii Acknowledgments I wish to thank the many people who have supported me during graduate school and whose efforts have made this dissertation possible. In particular, I am grateful to my thesis advisor, David MacMillan, for his advice and encouragement through every phase of my training as a chemist—from scrubbing fume hoods in Lewis Hall to making complex natural products. Special thanks are due to my Caltech thesis committee (Peter Dervan, John Bercaw, Rudolph Marcus, and Dave) and my Berkeley candidacy committee (Jean Fréchet, Carolyn Bertozzi, and Peter Vollhardt) for their valuable input and time. I would like to thank Larry Overman at UC Irvine for sparking my interest in organic synthesis, the opportunity to conduct undergraduate research in his lab, and his continued support ever since. I owe a great deal to everyone in the MacMillan group, past and present, for their friendship and professional collaboration the last five and a half years. Together, we’ve shaped a formidable research lab, and enjoyed hundreds of pizzas and birthday cakes along the way. I am especially indebted to Tehshik Yoon for his mentorship my first year, and his key contributions to project Claisen. A big thanks to my fellow classmate Jake Wiener for the countless days we spent rotovaping, talking, and mostly laughing together in lab.
    [Show full text]
  • The 3Rd Transatlantic Frontiers in Chemistry Symposium
    GUEST EDITORIAL DOI: 10.1002/chem.201303417 The 3rd Transatlantic Frontiers in Chemistry Symposium Anastassia N. Alexandrova,*[a] Stefan M. Huber,*[b] and Ali Tavassoli*[c] The 3rd Transatlantic Frontiers of Chemistry Symposium, set of topics that were grouped into related sessions. The held at Kloster Seeon in Germany on August 8–11, 2013 meeting started with an address by representatives of the or- brought together 60 early-career chemistry academics from ganizing committee (Gesellschaft Deutscher Chemiker, Germany (20), UK (18), USA (16) and for the first time, American Chemical Society, and Royal Society of Chemis- Brazil (6). The aims of the conference were to enable inter- try; Figure 2), followed by remarks from the conference national, multidisciplinary networking and collaboration op- chair, Prof. Dr. Hans-Dieter Arndt: “you are in one of the portunities in the relaxing settings of a beautiful old monas- most beautiful parts of Germany, with plenty of things to do tery by a lake (Figure 1). The program included a diverse and see in the area. Unfortunately you will be spending quite a bit of your time during the coming days in this lecture theater…” (Figure 3). Each delegate was then asked to standup and introduce them- selves, and it was immediately clear, that despite the involve- ment of only four national chemical societies, this was a truly international confer- ence, with multiple countries represented; a running theme of this section was that most delegates were dual nationals Figure 1. Kloster Seeon: the setting for the 3rd Transatlantic Frontiers of Chemistry Symposium; photo: A. and many were working in Alexandrova.
    [Show full text]
  • Unveiling Potent Photooxidation Behavior of Catalytic Photoreductants Karina Targos,‡ Oliver P
    Unveiling Potent Photooxidation Behavior of Catalytic Photoreductants Karina Targos,‡ Oliver P. Williams,‡ and Zachary K. Wickens* Department of Chemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706, United States. Supporting Information Placeholder 4 ABSTRACT: We describe a photocatalytic system that intersystem crossing. Despite tremendous effort in 4,5 reveals latent photooxidant behavior from one of the most photoredox catalyst design, excited state potentials reducing conventional photoredox catalysts, N- beyond roughly –2 and +2 V vs SCE remain difficult to 6 phenylphenothiazine (PTH). This aerobic photochemical achieve using conventional photocatalysis (Figure 1A). reaction engages difficult to oxidize feedstocks, such as Unfortunately, this redox window excludes numerous benzene, in C(sp2)–N coupling reactions through direct abundant hydrocarbon feedstocks from facile 7 oxidation. Mechanistic studies are consistent with activation photoinduced electron transfer. of PTH via photooxidation and that Lewis acid co-catalysts To overcome the energetic limitations intrinsic to scavenge inhibitors formed upon catalyst activation. conventional photoredox catalysis, König and coworkers recently designed a photocatalytic system that drives challenging reductive SET events using the energy of two photons rather than one. This consecutive photoninduced Reactions driven by single electron transfer (SET) are electron transfer (conPET)8 strategy relies on a catalytic pervasive in organic chemistry. Consequently, new photooxidant
    [Show full text]