DOCSLIB.ORG

Development of Copper-Catalyzed Electrophilic Trifluoromethylation And

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Development of Copper-Catalyzed Electrophilic Trifluoromethylation And Development of Copper-Catalyzed Electrophilic Trifluoromethylation and Exploiting Cu/Cu2O Nanowires with Novel Catalytic Reactivity Dissertation by Huaifeng Li In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy King Abdullah University of Science and Technology Thuwal, Kingdom of Saudi Arabia June, 2014 2 EXAMINATION COMMITTEE APPROVALS FORM The dissertation of Huaifeng Li is approved by the examination committee. Committee Chairperson: Prof. Kuo-Wei Huang Committee Member: Prof. Jorg Eppinger Committee Member: Prof. Yu Han Committee Member: Prof. Zhiping Lai 3 June, 2014 Huaifeng Li All Rights Reserved 4 ABSTRACT Development of Copper-Catalyzed Electrophilic Trifluoromethylation and Exploiting Cu/Cu2O Nanowires with Novel Catalytic Reactivity Huaifeng Li This thesis is based on research in Cu-catalyzed electrophilic trifluoromethylation and exploiting Cu/Cu2O nanowires with novel catalytic reactivity for developing of catalytic and greener synthetic methods. A large number of biological active pharmaceuticals and agrochemicals contain fluorine substituents (-F) or trifluoromethyl groups (-CF3) because these moieties often result in profound changes of their physical, chemical, and biological properties, such as metabolic stability and lipophilicity. For this reason, the introduction of fluorine or trifluoromethyl groups into organic molecules has attracted intensive attention. Among them, transition metal-catalyzed trifluoromethylation reactions has proved to be an efficient and reliable strategy to construct carbon-fluorine (C-F) and carbon- trifluoromethyl (C-CF3) bond. We have developed a catalytic process for the first time for trifluoromethylation of terminal alkynes with Togni’s reagent, affording trifluoromethylated acetylenes in good to excellent yields. The reaction is conducted at room temperature and exhibits tolerance to a range of functional groups. Derived from this discovery, the extension of work of copper catalyzed electrophilic trifluoromethylation were investigated which include the 5 electrophilic trifluoromethylation of arylsulfinate salts and electrophilic trifluoromethylation of organotrifluoroborates. Because of growing environmental concern, the development of greener synthetic methods has drawn much attention. Nano-sized catalysts are environment-friendly and an attractive green alternative to the conventional homogeneous catalysts. The nano-sized catalysts can be easily separated from the reaction mixture due to their insolubility and thus they can be used recycled. Notably, because of the high reactivities of nano-sized metal catalysts, the use of ligands can be avoided and the catalysts loadings can be reduced greatly. Moreover, the nano-sized catalysts can increase the exposed surface area of the active component, thereby enhancing the contact between reactants and catalyst dramatically. Based on the above-mentioned concepts and with the aim of achieving one “green and sustainable” approach, C-S bond formation and click reactions catalyzed by Cu/Cu2O nanowires were investigated. It was found that the recyclable core-shell structured Cu/Cu2O nanowires could be applied as a highly reactive catalysts for the cross-coupling reaction between aryl iodides and the cycloaddition of terminal alkynes and azides under ligand-free conditions. Furthermore, these results were the first report for the cross- coupling reaction and click reaction catalyzed by one-dimensional (1D) copper nanowires. 6 ACKNOWLEDGEMENTS First and foremost, I heartily thank Professor Kuo-Wei Huang, my advisor for offering me the great opportunity to work in his lab over the years. I am extremely grateful to him for transmitting me great ideas in chemistry from his unfathomable both chemistry and philosophy knowledge. Along the way, he trained me how to think about chemical problems and design innovative solutions for them in simple, yet excellent ways. He showed me how to analyze the experiment data and get the useful information, instead of just robotic scientific research. This dissertation would not have been possible without his continual guidance, advice and kind support that he grants me. Moreover, I am deeply grateful to his help for my family. He has been not only a forever-supportive teacher and supervisor to me but also a great human being. I was fortunate enough to be the first Ph.D. student of Professor Huang, and from him I learned not only knowledge and experimental skills, but also the persistent pursuit of higher quality in both academic and personal life. I would also like to thank our collaborators, Professor Zhiqiang Weng at the Fuzhou University and Professor Zhiping Lai at KAUST for their helpful advice and invaluable assistance on my doctoral work. Without these help, much of my work would not be achieved. I must acknowledge my thesis committee members Professor Jorg Eppinger, Professor Yu Han, and Professor Zhiping Lai for their time, guidance and helpful discussions throughout the course of this research. I would like to express my gratitude to Professor 7 Jorg Eppinger for his helpful comments and his exceptional knowledge. I would like to thank Professor Yu Han, who is a brilliant and extremely helpful chemist with his expertise and insights in chemistry. Professor Zhiping Lai is to be thanked not only for his service as my Ph.D. committee members but also his mentorship during our coorperation in copper nanowires project. I am also grateful to one of my mentors, Professor Jinbo Hu at the Shanghai Institute of Organic Chemistry (SIOC) who set an outstanding model for me to pursue in my life and scientific research, for introducing me into organic chemistry and recommending me joining the research group led by Professor Huang. I would also take this opportunity to thank all the talent members in Professor Huang’s lab who have worked with me, namely, Dr. Tao Chen, Dr. Weiguo Jia, Dr. Liangfeng Yao, Dr. Dirong Gong, Dr. Xiaoyu Guan, Dr. Lipeng He, Dr. Xiao Han, Dr. Bin Zheng, Dr. Zhenhua Dong, Dr. Qianyi Zhao, Dr. Lei Hu, Dr. Yupeng Pan, Dr. Chenglin Pan, Dr. Yuan Wang, Dr. Shixiong Min, Dr. Limin Yang, Dr. Xianbing Liu, Dr. Amol Hengne, Richmond Lee, Davin Tan, XiaoZhi Lim, Ahmed Elshewy and Maha Alhaddad. Without their numerous help, it would have been impossible for me to finish some of my projects. They had given me a lot of assistance not only in chemistry but also in life. I especially thank Dr. Wei Chen who provide me the nanowire catalysts and characterize the materials. He gave me too much help during my research work. I also want to express my appreciation to the members of core lab at KAUST for technical support. I especially thank Dr. Xianrong Guo for NMR experiments, Dr. Liang 8 Li for X-ray characterization, Dr. Qingxiao Wang for microscopy characterization, Dr. Zeyad A. Al-Tallaand for HRMS, and Dr. Mustafa Altunkaya for element analysis. My appreciation also goes to my friends and colleagues and the department faculty and staff for making my time at KAUST a great experience. I would like to thank all my good friends in KAUST Catalysis Center (KCC) for their kind support. My deepest appreciation goes to my family for their selflessly support over the past years. Words cannot express my gratitude for their support. Without their help, I could not have completed this work. 9 TABLE OF CONTENTS EXAMINATION COMMITTEE APPROVALS FORM ............................................. 2 ABSTRACT ....................................................................................................................... 4 ACKNOWLEDGEMENTS ............................................................................................. 6 TABLE OF CONTENTS ................................................................................................. 9 LIST OF ABBREVIATIONS ........................................................................................ 12 LIST OF SCHEMES ...................................................................................................... 15 LIST OF FIGURES ........................................................................................................ 19 LIST OF TABLES .......................................................................................................... 21 Chapter 1 ......................................................................................................................... 23 Introduction of Copper-Mediated Reactions: A Short Survey from A Historical Contextual Perspective ................................................................................................... 23 1.1 Historical background ............................................................................................. 24 1.2 Renaissance of copper mediated reactions: progress in modern copper chemistry 30 1.2.1 Pioneering studies on the ligand effect for the copper catalyzed reactions ...... 31 1.2.2 Copper mediated regular cross-coupling reactions .......................................... 35 1.2.2.1 C-N bonds cross-coupling reactions .......................................................... 35 1.2.2.2 C-O bonds cross-coupling reactions .......................................................... 44 1.2.2.3 C-S bonds cross-coupling reactions ........................................................... 50 1.2.3 Copper mediated oxidative cross-coupling reactions ....................................... 53 1.2.4 Copper mediated Umpolung cross-coupling reactions using electrophilic nitrogen sources ........................................................................................................
Load more

Recommended publications
  • Shelf-Stable Electrophilic Trifluoromethylating Reagents: a Brief Historical Perspective
    Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective Norio Shibata*1, Andrej Matsnev1 and Dominique Cahard*2 Review Open Access Address: Beilstein J. Org. Chem. 2010, 6, No. 65. doi:10.3762/bjoc.6.65 1Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya Received: 15 March 2010 466-8555, Japan and 2UMR 6014 CNRS – C.O.B.R.A. Université et Accepted: 21 May 2010 INSA de Rouen, 1 rue Tesnière, 76130 Mont Saint Aignan, France Published: 16 June 2010 Email: Guest Editor: D. O'Hagan Norio Shibata* - [email protected]; Dominique Cahard* - [email protected] © 2010 Shibata et al; licensee Beilstein-Institut. License and terms: see end of document. * Corresponding author Keywords: asymmetric synthesis; electrophilic; fluorine; reagent; trifluoromethylation Abstract Since the discovery by Yagupolskii and co-workers that S-trifluoromethyl diarylsulfonium salts are effective for the trifluoro- methylation of thiophenolates, the design and synthesis of electrophilic trifluoromethylating reagents have been extensively researched in both academia and industry, due to the significant unique features that trifluoromethylated compounds have in phar- maceuticals, agricultural chemicals, and functional materials. Several effective reagents have been developed by the groups of Yagupolskii, Umemoto, Shreeve, Adachi, Magnier, Togni and Shibata. Due to the high stability and reactivity of these reagents, a series of Umemoto reagents, Togni reagent and Shibata reagent are now commercially available. In this review, we wish to briefly provide a historical perspective of the development of so-called “shelf-stable electrophilic trifluoromethylating reagents”, although this field is in constant development. Review The chemistry of fluoro-organic compounds is one of the areas [3].
    [Show full text]
  • Perfluoro-3-Ethyl-2,4-Dimethyl-3
    Journal of Fluorine Chemistry 227 (2019) 109370 Contents lists available at ScienceDirect Journal of Fluorine Chemistry journal homepage: www.elsevier.com/locate/fluor Perfluoro-3-ethyl-2,4-dimethyl-3-pentyl persistent radical: A new reagent T for direct, metal-free radical trifluoromethylation and polymer initiation ⁎ ⁎ ⁎ Haibo Meia, Jianlin Hana, , Sarah Whiteb, , Greg Butlerb, Vadim A. Soloshonokc,d, a College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, China b Oakwood Chemical, Inc. 730 Columbia Hwy. N, Estill, SC, 29918, USA c Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018, San Sebastián, Spain d IKERBASQUE, Basque Foundation for Science, María Díaz de Haro 3, Plaza Bizkaia, 48013, Bilbao, Spain ARTICLE INFO ABSTRACT Keywords: This review comprehensively profiles perfluoro-3-ethyl-2,4-dimethyl-3-pentyl persistent radical (PPFR) asanew Fluorine reagent for radical trifluoromethylation, trifluoromethylation/fluorination and polymer initiation. The PPFRis Trifluoromethylation perfectly stable at ambient conditions, but at temperatures above 80 °C undergoes β-scission to generate tri- Persistent radical fluoromethyl radical. This property can be used to initiate various chain-polymerization or trifluoromethylation Fluorination reactions. The unique feature of this process, distinguishing it from all other known methods for ·CF3-radical Polymer generation, is that the radical is produced under neutral, inert and additive-free
    [Show full text]
  • Advances in Catalytic Enantioselective Fluorination, Mono‑,Di‑, and Trifluoromethylation, and Trifluoromethylthiolation Reactions ‡ ‡ † Xiaoyu Yang, Tao Wu, Robert J
    Review pubs.acs.org/CR Advances in Catalytic Enantioselective Fluorination, Mono‑,Di‑, and Trifluoromethylation, and Trifluoromethylthiolation Reactions ‡ ‡ † Xiaoyu Yang, Tao Wu, Robert J. Phipps, and F. Dean Toste* Department of Chemistry, University of California, Berkeley, California 94720, United States 6. Catalytic Enantioselective Trifluoromethylthiola- tion 865 7. Summary and Outlook 866 Author Information 866 Corresponding Author 866 Present Address 866 Author Contributions 866 Notes 866 CONTENTS Biographies 866 Acknowledgments 867 1. Introduction 826 References 867 2. Catalytic Enantioselective Fluorination 827 2.1. Electrophilic Fluorination 827 2.1.1. Metal-Catalyzed Fluorination Involving 1. INTRODUCTION Enolates 827 Despite being largely absent from natural products and 2.1.2. Metal-Catalyzed Fluorination Not In- biological processes, fluorine plays a conspicuous and volving Enolates 834 increasingly important role within pharmaceuticals and agro- 2.1.3. Organocatalytic Electrophilic Fluorina- − chemicals, as well as in materials science.1a c Indeed, as many as tion 835 35% of agrochemicals and 20% of pharmaceuticals on the 2.1.4. Fluorination Using Multiple Catalysts 846 market contain fluorine.1d Fluorine is the most electronegative 2.1.5. One-Pot and Tandem Processes 848 element in the periodic table, and the introduction of one or 2.2. Nucleophilic Fluorination 850 more fluorine atoms into a molecule can result in greatly 3. Catalytic Enantioselective Trifluoromethylation perturbed properties. Fluorine substituents can potentially and Perfluoroalkylation 853 impact a number of variables, such as the acidity or basicity of 3.1. Asymmetric Nucleophilic Trifluoromethyla- neighboring groups, dipole moment, and properties such as tion 853 lipophilicity, metabolic stability, and bioavailability. The 3.1.1. Overview of Nucleophilic Trifluorome- multitude of effects that can arise from the introduction of thylation 853 fluorine in small molecules in the context of medicinal 3.1.2.
    [Show full text]
  • CV-PSB-August 2020
    Curriculum Vitae Phil S. Baran Appointment: Scripps Research Professor, Department of Chemistry 10550 North Torrey Pines Road, BCC-436 La Jolla, California 92037 Telephone: (858) 784-7373 Facsimile: (858) 784-7575 Email: [email protected] Website: www.scripps.edu/chem/baran/ January, 2013 Darlene Shiley Professor of Chemistry April, 2009 Member, Skaggs Institute for Chemical Biology June, 2008 Professor of Chemistry July, 2006 Associate Professor of Chemistry (with Tenure) June, 2003 Assistant Professor of Chemistry Date/Place of Birth: 10 Aug 1977 / Denville, NJ, USA Citizenship: United States Education 2001 – 2003 Postdoctoral Associate Advisor: Professor E.J. Corey Harvard University, Cambridge, Massachusetts 1997 – 2001 Ph.D. Graduate Student in Chemistry Advisor: Professor K.C. Nicolaou The Scripps Research Institute, La Jolla, California 1995 – 1997 B.S. with Honors in Chemistry Advisor: Professor D.I. Schuster New York University, New York, New York 1991 – 1995 Simultaneous high school graduation from Mt. Dora High School and A.A. degree with honors, Lake Sumter Community College, Florida Awards • Inhoffen Medal, 2019 • Manchot Research Professorship, 2017 • Member, The National Academy of Sciences, 2017 • Emanuel Merck Lectureship, 2017 • Blavatnik National Laureate in Chemistry, 2016 • ACS Elias J. Corey Award, 2016 • Member, American Academy of Arts and Sciences, 2015 • College of Arts and Science Alumni Distinguished Service Award, New York University, 2015 • Reagent of the Year Award (EROS), 2015 • Mukaiyama Award, 2014 •
    [Show full text]
  • Development of Palladium-Catalyzed Decarboxylative Allylation of Electron-Deficient Sulfones: Method Development and Mechanistic Studies
    Development of Palladium-Catalyzed Decarboxylative Allylation of Electron-Deficient Sulfones: Method Development and Mechanistic Studies by Monica Anne Gill A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry Carleton University Ottawa, Ontario © 2015, Monica Anne Gill Abstract Palladium-catalyzed decarboxylative allylation is a powerful method of carbon-carbon bond construction. This methodology relies on an electron- withdrawing group to promote the reaction. The use of sulfones in decarboxylative allylation has been explored using the trifluoromethylsulfonyl (triflyl) group, as well as the bis(3,5-trifluoromethyl)phenylsulfonyl (BTMP) group. These substrates are highly reactive at room temperature (triflyl) and 50 oC (BTMP sulfones). A detailed mechanistic study using deuterium-labelled substrates was performed to understand the origin of the protonation side-product. It was proposed that a β- hydride elimination from the η1 allyl on palladium could generate a palladium hydride intermediate along with an allene. Although small amounts of deuterium incorporation were observed in the protonated products, the proposed mechanism could not be the major pathway. Using isotopically labelled ligand, however, all protonation was supressed. This suggests that the origin of the proton is actually from the ligand and that kinetic isotope effects may be responsible for inhibiting the protonation pathway with labelled ligand. ii Acknowledgments I would like to thank Dr. Jeff Manthorpe for giving me the chance to pursue my PhD in his lab. I always appreciated Jeff’s enthusiasm for organic chemistry as well as his vast knowledge of the subject.
    [Show full text]
  • Innate C-H Trifluoromethylation of Heterocycles
    Innate C-H trifluoromethylation of heterocycles Yining Ji1, Tobias Brueckl1, Ryan D. Baxter, Yuta Fujiwara, Ian B. Seiple, Shun Su, Donna G. Blackmond, and Phil S. Baran2 Department of Chemistry, The Scripps Research Institute, 10650 North Torrey Pines Road, La Jolla, CA 92037 Edited* by Stephen L. Buchwald, Massachusetts Institute of Technology, Cambridge, MA, and approved July 18, 2011 (received for review June 6, 2011) Direct methods for the trifluoromethylation of heteroaromatic systems are in extremely high demand in nearly every sector of chemical industry. Here we report the discovery of a general pro- cedure using a benchtop stable trifluoromethyl radical source that functions broadly on a variety of electron deficient and rich hetero- aromatic systems and demonstrates high functional group toler- ance. This C-H trifluoromethylation protocol is operationally simple (avoids gaseous CF3I), scalable, proceeds at ambient tem- perature, can be used directly on unprotected molecules, and is demonstrated to proceed at the innately reactive positions of the substrate. The unique and orthogonal reactivity of the trifluor- omethyl radical relative to aryl radicals has also been investigated on both a complex natural product and a pharmaceutical agent. Finally, preliminary data suggest that the regioselectivity of C-H trifluoromethylation can be fine-tuned simply by judicious solvent choice. medicinal chemistry ∣ C-H functionalization ∣ synthetic methodology he trifluoromethyl group is becoming an increasingly common Ttrait among molecules found in billion-dollar pharmaceuti- cals, agrochemicals, liquid crystals, dyes, and polymers (1–6). The inclusion of this motif and the unique properties its presence elicits is a testament to the success of chemical synthesis, as it is notably absent in Nature.
    [Show full text]
  • Template for Electronic Submission to ACS Journals
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Apollo Real-time spectroscopic analysis enabling quantitative and safe consumption of fluoroform during nucleophilic trifluoromethylation in flow. Biagia Musio,* Elena Gala,† Steven V. Ley* Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K. *Email: [email protected] (B. Musio); [email protected] (S. V. Ley). ABSTRACT: The productive use of toxic waste materials derived from industrial processes is one of the main goals of modern chemical research to increase sustainability of the large scale production. Here we devise a simple and robust strategy for the utilization of trifluoromethane, obtained in large quantities from polytetrafluoroethylene (PTFE) manufacture, and the conversion of this greenhouse gas into valuable fluorinated compounds. The generation of the trifluoromethyl carbanion and its direct and complete consumption through trapping with a number of electrophiles were achieved by a fully contained flow reactor setup. The adoption of modern in-line analytical tools, such as portable FT-IR and NMR devices, allowed the accurate reagent dosing with considerable benefits in terms of controlling the environmental impact during this continuous process. The advantages of the method, with respect to the batch procedure, will be discussed and demonstrated experimentally. 1 KEYWORDS: trifluoromethylation, continuous process, in-line analysis, bench-top NMR, fluoroform. INTRODUCTION There is a clear need to develop modern synthetic strategies which employ renewable starting materials. Furthermore, there is also a need to convert waste materials derived from certain industrial processes into valuable synthetic compounds improving the sustainability of large scale production.1-3 A case in point is the industrial manufacture of PTFE which generates very 4 large amounts of trifluoromethane (CF3H) as a by-product.
    [Show full text]
  • Multidisciplinary Chemistry Journals
    Best of Multidisciplinary Chemistry Journals FREE access to top articles Inspiring Chemistry A journal of www.angewandte.org FREE Sample Copy Chair of the Editor-in-Chief: Editorial Board: Peter Gölitz Alois Fürstner (Mülheim) Highlights: Editorial Board: • Free App available: bit.ly/CHEMAPPS Annette G. Beck-Sickinger Andreas Kreimeyer - “The Angew. Chem. App is fantastic. (Leipzig) (Ludwigshafen) Very intuitive and informative. It is a Matthias Beller (Rostock) Christof M. Niemeyer very nice way to quickly find content Hans-Joachim Böhm (Basel) (Dortmund) relevant to one’s work” Stefan Buchholz (Essen) Wolfgang Parak (Marburg) (Chad A. Mirkin) Thomas Carell (Munich) Ferdi Schüth (Mülheim) - “I use the Angewandte app all the Claus Feldmann (Karlsruhe) Petra Schwille (Dresden) time. I love it! It’s great to be able Roland Fischer (Bochum) Martin Suhm (Göttingen) to download entire issues for offline Thomas Geelhaar (Darmstadt) Brigitte Voit (Dresden) reading.” (Phil S. Baran) Stefan Grimme (Bonn) Herbert Waldmann (Dortmund) • Follow us on Twitter and Facebook Hansjörg Grützmacher (Zurich) Hanno Wild (Wuppertal) International Advisory Board: Comprising 44 world-renowned scientists, including Nobel Laureates Roald Hoffmann, Jean-Marie Lehn, Ryoji Noyori, and Ahmed Zewail. “Angewandte Chemie combines a unique portfolio of publication types in a highly attractive format. Reading the journal daily online ensures that I keep up to date with the progress in my own fields of research and all other areas of chemistry.” (François Diederich) 2 Mixed Transition Metal Oxides: Design, Synthesis, and Energy Related Applications Changzhou Yuan, Hao Bin Wu, Yi Xie*, Xiong Wen (David) Lou* Full of energy: Recent advances in the rational design and synthesis of mixed transition-metal oxides (MTMOs, designated as AxB3−xO4) with controllable compositions and structures and their applications in various electrochemical energy storage/ conversion technologies are summarized and discussed (see picture).
    [Show full text]
  • Cu-Catalyzed Trifluoromethylation of Aryl Iodides with Trifluoromethylzinc Reagent Prepared in Situ from Trifluoromethyl Iodide
    Cu-catalyzed trifluoromethylation of aryl iodides with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide Yuzo Nakamura, Motohiro Fujiu, Tatsuya Murase, Yoshimitsu Itoh, Hiroki Serizawa, Kohsuke Aikawa and Koichi Mikami* Letter Open Access Address: Beilstein J. Org. Chem. 2013, 9, 2404–2409. Department of Applied Chemistry, Graduate School of Science and doi:10.3762/bjoc.9.277 Engineering, Tokyo Institute of Technology, 2-12-1-H-113 O-okayama, Meguro-ku, Tokyo 152-8552, Japan Received: 02 September 2013 Accepted: 10 October 2013 Email: Published: 08 November 2013 Koichi Mikami* - [email protected] This article is part of the Thematic Series "Organo-fluorine chemistry III" * Corresponding author and is dedicated to the memory of the late Professor Nobuo Ishikawa on the occasion of his 23rd Kai-Ki. Keywords: organo-fluorine; Ruppert–Prakash reagent; trifluoromethyl; Guest Editor: D. O'Hagan trifluoromethylation; trifluoromethyl zinc © 2013 Nakamura et al; licensee Beilstein-Institut. License and terms: see end of document. Abstract The trifluoromethylation of aryl iodides catalyzed by copper(I) salt with trifluoromethylzinc reagent prepared in situ from trifluo- romethyl iodide and Zn dust was accomplished. The catalytic reactions proceeded under mild reaction conditions, providing the corresponding aromatic trifluoromethylated products in moderate to high yields. The advantage of this method is that additives such as metal fluoride (MF), which are indispensable to activate silyl groups for transmetallation
    [Show full text]
  • Chem. Sci., 3, 633-658
    View Online / Journal Homepage / Table of Contents for this issue Chemical Science Dynamic Article LinksC< Cite this: Chem. Sci., 2012, 3, 633 www.rsc.org/chemicalscience PERSPECTIVE Synergistic catalysis: A powerful synthetic strategy for new reaction development Anna E. Allen and David W. C. MacMillan* Received 11th November 2011, Accepted 2nd December 2011 DOI: 10.1039/c2sc00907b Synergistic catalysis is a synthetic strategy wherein both the nucleophile and the electrophile are simultaneously activated by two separate and distinct catalysts to afford a single chemical transformation. This powerful catalysis strategy leads to several benefits, specifically synergistic catalysis can (i) introduce new, previously unattainable chemical transformations, (ii) improve the efficiency of existing transformations, and (iii) create or improve catalytic enantioselectivity where stereocontrol was previously absent or challenging. This perspective aims to highlight these benefits using many of the successful examples of synergistic catalysis found in the literature. 1. Introduction emerged as a powerful new mechanistic approach to reaction engineering. In its simplest form (Fig. 1), synergistic catalysis Catalysis is, without question, one of the most efficient and involves the concurrent activation of both a nucleophile and an powerful mechanistic strategies for identifying or engineering electrophile using distinct catalysts. This simultaneously creates new chemical reactions. Within the realm of chemical synthesis, two reactive species, one with a higher HOMO (highest occupied traditional catalytic pathways generally rely on the interaction of molecular orbital) and the other with a lower LUMO (lowest a unique catalyst with a single substrate, thereby lowering the unoccupied molecular orbital), in comparison to the respective energetic barrier to bond formation with a second, unactivated ground state starting materials.
    [Show full text]
  • Fluoroform Synthesis and Uses Thereof in the Preparation of Trifluoromethylated Compounds
    (19) TZZ Z_T (11) EP 2 784 055 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 01.10.2014 Bulletin 2014/40 C07C 17/093 (2006.01) (21) Application number: 13305392.6 (22) Date of filing: 28.03.2013 (84) Designated Contracting States: (72) Inventors: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB • Jubault, Philippe GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO 76160 Preaux (FR) PL PT RO RS SE SI SK SM TR • Pannecoucke, Xavier Designated Extension States: 76150 Maromme (FR) BA ME • Ivashkin, Pavel 76130 Mont Saint Aignan (FR) (71) Applicants: • Institut National des Sciences (74) Representative: Regimbeau Appliquées de Rouen (INSA) 20, rue de Chazelles 76801 St-Etienne du Rouvray Cedex (FR) 75847 Paris Cedex 17 (FR) • Centre National de la Recherche Scientifique (CNRS) 75016 Paris (FR) (54) Fluoroform synthesis and uses thereof in the preparation of trifluoromethylated compounds (57) The present invention relates to a process to prepare fluoroform (CHF3), notably radio labelled with fluorine- 18, comprising a substitution reaction between CHAF 2 and a fluoride salt, wherein A represents or as well as a process to prepare a composition comprising copper-based or silver-based trifluoromethylated reagents using notably the fluoroform thus prepared and the use of a composition comprising copper-based trifluoromethylated reagents or a mixture comprising a copper salt and a composition comprising silver- based trifluoromethylated reagents as a trifluoromethylating agent, notably radio labelled with fluorine- 18. EP 2 784 055 A1 Printed by Jouve, 75001 PARIS (FR) EP 2 784 055 A1 Description [0001] The present patent application relates to a process to prepare fluoroform, notably in a radiolabelled form, as well as the use thereof to prepare trifluoromethylated compounds via the preparation of copper-based or silver-based 5 trifluoromethylated reagents.
    [Show full text]
  • Introduction and Motivation
    Small Molecule Organic Semiconductors as Efficient Visible Light-active Photocatalysts Dissertation Zur Erlangung des Grades „Doktor der Naturwissenschaften“ im Promotionsfach Chemie dem Fachbereich Chemie, Pharmazie und Geowissenschaften der Johannes Gutenberg-Universität Mainz Lei Wang Geboren in Yining, China Mainz, July 2017 Dekan: 1. Gutachter: 2. Gutachter: Tag der mündlichen Prüfung: 25-09-2017 Affidavit I hereby confirm that I have completed the present dissertation independently and without inadmissible external support. I have not used any sources or tools other than those indicated and have identified literal and analogous quotations. Furthermore, I confirm that this thesis has not yet been submitted as part of another examination process neither in identical nor in similar form. Place, date: Signature: Einführung Diese Arbeit befasst sich mit neuen konzeptionellen Designs für die Entwicklung von niedermolekularen organischen Halbleitern als effiziente Photokatalysatoren für organische Photoredox-Reaktionen. Sichtbares Licht wurde als Energiequelle benutzt. Ziel der Arbeit war es, eine neue Klasse von metallfreien Photokatalysatoren auf Basis von organischen Halbleitern als Alternative von traditionellen Übergangsmetallkomplexen zu etablieren und deren Einsatzbereich zu untersuchen und zu erweitern. Zunächst wurde ein allgemeines Konstruktionsprinzip von niedermolekularen organischen Halbleitern präsentiert, um entscheidende Anforderungen zu erfüllen wie: 1) Absorption im sichtbaren Bereich, 2) ausreichendes Photoredoxpotential
    [Show full text]