Recent Advances on Mechanistic Studies on C–H Activation
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Carbene and Nitrene Transfer Reactions Joseph B
University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 11-19-2014 Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions Joseph B. Gill University of South Florida, [email protected] Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the Organic Chemistry Commons Scholar Commons Citation Gill, Joseph B., "Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions" (2014). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/5484 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Co(II) Based Metalloradical Catalysis: Carbene and Nitrene Transfer Reactions by Joseph B. Gill A dissertation in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry College of Arts and Sciences University of South Florida Major Professor: X. Peter Zhang, Ph.D. Jon Antilla, Ph.D Jianfeng Cai, Ph.D. Edward Turos, Ph.D. Date of Approval: November 19, 2014 Keywords: cyclopropanation, diazoacetate, azide, porphyrin, cobalt. Copyright © 2014, Joseph B. Gill Dedication I dedicate this work to my parents: Larry and Karen, siblings: Jason and Jessica, and my partner: Darnell, for their constant support. Without all of you I would never have made it through this journey. Thank you. Acknowledgments I would like to thank my advisor, Professor X. Peter Zhang, for his support and guidance throughout my time working with him. -
Insertion Reactions • Oxidative Addition and Substitution Allow Us to Assemble 1E and 2E Ligands on the Metal, Respectively
Insertion Reactions • Oxidative addition and substitution allow us to assemble 1e and 2e ligands on the metal, respectively. • With insertion, and its reverse reaction, elimination, we can now combine and transform these ligands within the coordination sphere, and ultimately expel these transformed ligands to form free organic compounds. • There are two main types of insertion 1) 1,1 insertion in which the metal and the X ligand end up bound to the same (,)(1,1) atom 2) 1,2 insertion in which the metal and the X ligand end up bound to adjacent (1,2) atoms of an L‐type ligand. 1 • The type of insertion observed in any given case depends on the nature of the 2e inserting ligand. • For example: CO gives only 1,1 insertion ethylene gives only 1,2 insertion, in which the M and the X end up on adjacent atoms of what was the 2e X‐type ligand. In general, η1 ligands tend to give 1,1 insertion and η2 ligands give 1,2 insertion • SO2 is the only common ligan d tha t can give bthboth types of itiinsertion; as a ligan d, SO2 can be η1 (S) or η2 (S, O). • In principle, insertion reactions are reversible, but just as we saw for oxidative addition and reductive elimination previously, for many ligands only one of the two possible directions is observed in practice, probably because this direction is strongly favored thermodynamically. 2 •A2e vacant site is generated by 1,1 and 1,2 insertion reactions. • Thissite can be occupidied byanextlternal 2e ligan d and the itiinsertion prodtduct tdtrapped. -
Organic Synthesis: New Vistas in the Brazilian Landscape
Anais da Academia Brasileira de Ciências (2018) 90(1 Suppl. 1): 895-941 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 http://dx.doi.org/10.1590/0001-3765201820170564 www.scielo.br/aabc | www.fb.com/aabcjournal Organic Synthesis: New Vistas in the Brazilian Landscape RONALDO A. PILLI and FRANCISCO F. DE ASSIS Instituto de Química, UNICAMP, Rua José de Castro, s/n, 13083-970 Campinas, SP, Brazil Manuscript received on September 11, 2017; accepted for publication on December 29, 2017 ABSTRACT In this overview, we present our analysis of the future of organic synthesis in Brazil, a highly innovative and strategic area of research which underpins our social and economical progress. Several different topics (automation, catalysis, green chemistry, scalability, methodological studies and total syntheses) were considered to hold promise for the future advance of chemical sciences in Brazil. In order to put it in perspective, contributions from Brazilian laboratories were selected by the citations received and importance for the field and were benchmarked against some of the most important results disclosed by authors worldwide. The picture that emerged reveals a thriving area of research, with new generations of well-trained and productive chemists engaged particularly in the areas of green chemistry and catalysis. In order to fulfill the promise of delivering more efficient and sustainable processes, an integration of the academic and industrial research agendas is to be expected. On the other hand, academic research in automation of chemical processes, a well established topic of investigation in industrial settings, has just recently began in Brazil and more academic laboratories are lining up to contribute. -
And Intermolecular Cyclopropanation by Co(II)- Based Metalloradical Catalysis Xue Xu University of South Florida, [email protected]
University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School January 2012 Asymmetric Intra- and Intermolecular Cyclopropanation by Co(II)- Based Metalloradical Catalysis Xue Xu University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the American Studies Commons, and the Organic Chemistry Commons Scholar Commons Citation Xu, Xue, "Asymmetric Intra- and Intermolecular Cyclopropanation by Co(II)- Based Metalloradical Catalysis" (2012). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/4262 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Asymmetric Intra- and Intermolecular Cyclopropanation by Co(II)- Based Metalloradical Catalysis by Xue(Snow) Xu A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Chemistry College of Arts and Sciences University of South Florida Major Professor: X. Peter Zhang, Ph.D. Jon Antilla, Ph.D. Mark L. McLaughlin, Ph.D. Wayne Guida, Ph.D. Date of Defense: June 20th, 2012 Keywords: cobalt, porphyrin, catalysis, cyclopropanation, carbene, diazo Copyright © 2012, Xue Xu DEDICATION I dedicate this dissertation to my parents and my husband, without their caring support, it would not have been possible. ACKNOWLEGEMENTS I need to begin with thanking Dr. Peter Zhang for his continuous guidance and support over the last 5 and half years. Especially for encouraging me to achieving my potential as a researcher and setting an example of dedication to science that is admirable. -
IODINE Its Properties and Technical Applications
IODINE Its Properties and Technical Applications CHILEAN IODINE EDUCATIONAL BUREAU, INC. 120 Broadway, New York 5, New York IODINE Its Properties and Technical Applications ¡¡iiHiüíiüüiütitittüHiiUitítHiiiittiíU CHILEAN IODINE EDUCATIONAL BUREAU, INC. 120 Broadway, New York 5, New York 1951 Copyright, 1951, by Chilean Iodine Educational Bureau, Inc. Printed in U.S.A. Contents Page Foreword v I—Chemistry of Iodine and Its Compounds 1 A Short History of Iodine 1 The Occurrence and Production of Iodine ....... 3 The Properties of Iodine 4 Solid Iodine 4 Liquid Iodine 5 Iodine Vapor and Gas 6 Chemical Properties 6 Inorganic Compounds of Iodine 8 Compounds of Electropositive Iodine 8 Compounds with Other Halogens 8 The Polyhalides 9 Hydrogen Iodide 1,0 Inorganic Iodides 10 Physical Properties 10 Chemical Properties 12 Complex Iodides .13 The Oxides of Iodine . 14 Iodic Acid and the Iodates 15 Periodic Acid and the Periodates 15 Reactions of Iodine and Its Inorganic Compounds With Organic Compounds 17 Iodine . 17 Iodine Halides 18 Hydrogen Iodide 19 Inorganic Iodides 19 Periodic and Iodic Acids 21 The Organic Iodo Compounds 22 Organic Compounds of Polyvalent Iodine 25 The lodoso Compounds 25 The Iodoxy Compounds 26 The Iodyl Compounds 26 The Iodonium Salts 27 Heterocyclic Iodine Compounds 30 Bibliography 31 II—Applications of Iodine and Its Compounds 35 Iodine in Organic Chemistry 35 Iodine and Its Compounds at Catalysts 35 Exchange Catalysis 35 Halogenation 38 Isomerization 38 Dehydration 39 III Page Acylation 41 Carbón Monoxide (and Nitric Oxide) Additions ... 42 Reactions with Oxygen 42 Homogeneous Pyrolysis 43 Iodine as an Inhibitor 44 Other Applications 44 Iodine and Its Compounds as Process Reagents ... -
Insertion Reactions of Isocyanides Into the Metal-C(Sp3) Bonds of Ylide Complexes
Journal of Organometallic Chemistry 894 (2019) 61e66 Contents lists available at ScienceDirect Journal of Organometallic Chemistry journal homepage: www.elsevier.com/locate/jorganchem Insertion reactions of isocyanides into the Metal-C(sp3) bonds of ylide complexes ** * María-Teresa Chicote a, , Isabel Saura-Llamas a, , María-Francisca García-Yuste a, Delia Bautista b, Jose Vicente a a Grupo de Química Organometalica, Departamento de Química Inorganica, Facultad de Química, Universidad de Murcia, Spain b ACTI, Universidad de Murcia, E-30100, Murcia, Spain article info abstract Article history: The synthesis of the previously reported complexes [Pd{(C,CeCHCO2R)2PPh2}(m-Cl)]2 (R ¼ Me (1), Et (2)) Received 10 January 2019 has been considerably improved by reacting the phosphonium salts [Ph2P(CH2CO2R)2]Cl with Pd(OAc)2. Received in revised form t Complexes 1 and 2 react with isocyanides R'NC (R’ ¼ C6H4Me2-2,6 (Xy), C6H4I-2 and Bu) to give com- 29 April 2019 plexes of the type [Pd{C,C-{C(CO R) ¼ C(NHR0)}(CHCO R)}PPh }Cl(CNR0)], resulting from the insertion of Accepted 5 May 2019 2 2 2 the unsaturated molecule in one of their PdeC bonds and the hydrogen transfer from the methine CH to Available online 11 May 2019 the iminobenzoyl nitrogen. These are the first insertion reactions observed in the PdeC bond of a P-ylide complex. The crystal structure of the complex [Pd{C,C-{C(CO Me)¼C(NHXy)}(CHCO Me)}PPh }Cl(CNXy)] Keywords: 2 2 2 Palladacycles (3) is reported. © Insertion reactions 2019 Elsevier B.V. All rights reserved. -
Section I Haloakanes
SECTION I HALOAKANES Compounds derived from alkanes by the replacement of one or more Hydrogen atoms by corresponding number of halogen atoms ( fluorine, chlorine, bromine or iodine) are termed as haloalkanes. Alkyl halides are represented by general formula CnH2n+1X, here X is halogen atom ORBITAL STRUCTURE In alkyl halides, carbon-halogen σ bond is formed by overlap of sp3 hybrid orbital of carbon and half filled valence p-orbital of halogen atom: Haloalkanes may be classified on the basis of number of halogen atoms (1) Monohalogen derivatives One halogen atom is attached to carbon atom. Its general formula is CnH2n+1X Example CH3Cl ( methyl chloride). (2) Dihalogen derivatives These are derived by replacement of two hydrogen atoms by two halogen atoms Dihalides derivatives are of three types (a) Gem-dihalides Halogen atoms are attached to same carbon atom. These are called alkylidene halides. 1 of 23 pages www.spiroacademy.com HALOALKANES AND HALOARENES www.spiroacademy.com (b) Vic-dihalides Halogen atoms are attached to adjacent (vicinal) carbon atoms. These are termed as alkylene halides. (c) α – ω halides ( terminal halides) Halogen atoms are attached to terminal carbon atoms. These are also called polymethyl halides Br – CH2 – CH2 – CH2 - Br Trimethyl di bromide ( 1,3 – dibromopropane) (3) Trihalogen derivatives Trihalogen derivatives are derived by replacing three hydrogen atoms by three halogen atoms. General formula is CnH2n-1X 2 of 23 pages www.spiroacademy.com HALOALKANES AND HALOARENES www.spiroacademy.com CLASSIFICATION OF MONOHALOGEN COMPOUND (1) Alkyl halides are classified as primary 1O, secondary 2O, tertiary 3O depending upon nature of carbon to which halogen is attached (2) Compounds containing sp3 , C – X bond (a) Alkyl halides CH3 – CH2 – CH2 – Cl ( 1- chloropropane) (b) Allylic carbon Halogen atom attached to allylic carbon. -
Experimental and Ab Initio Studies of Formation, Thermolysis, and Molecular and Electronic Structures of 3,6-Diphenyl-1-Propanesulfenimido-1,2,4,5-Tetrazine
J. Am. Chem. Soc. 2000, 122, 2087-2095 2087 Nucleophile-Induced Intramolecular Dipole 1,5-Transfer and 1,6-Cyclization: Experimental and ab Initio Studies of Formation, Thermolysis, and Molecular and Electronic Structures of 3,6-Diphenyl-1-propanesulfenimido-1,2,4,5-tetrazine Piotr Kaszynski*,† and Victor G. Young, Jr.‡ Contribution from the Organic Materials Research Group, Department of Chemistry, Vanderbilt UniVersity, NashVille, Tennessee 37235, and X-ray Crystallographic Laboratory, Department of Chemistry, UniVersity of Minnesota, Twin Cities, Minnesota 55455 ReceiVed NoVember 1, 1999 Abstract: Reaction of dichlorobenzaldazine (2) with sodium azide followed by 1-propanethiol/Et3N furnished tetrazine ylide 1 as the main product. The structure of this unprecedented ylide was confirmed with single- crystal X-ray analysis [C17H17N5S, monoclinic P21/na) 6.8294(4) Å, b ) 13.6781(9) Å, c ) 17.5898(12) Å, â ) 90.666(1)°, Z ) 4] and favorably compared with the results of ab initio calculations. The mechanisms of formation of the ylide and its thermal decomposition to 2,5-diphenyltetrazine (5) were investigated using ab initio methods and correlated with the experimental observations. The results suggest that formation of 1 involves intramolecular cyclization of a nitrile imine and thermolysis of 1 might generate a sulfenylnitrene. The formation of 1 is considered to be the first example of a potentially more general reaction. Introduction Results and Discussion Intramolecular reactions of 1,3-dipoles provide one of the Synthesis of 1. 3,6-Diphenyl-1-propanesulfenimido-1,2,4,5- most versatile ways to construct heterocyclic rings.1 Among tetrazine (1) was obtained in a one-pot reaction. -
Therapeutic Review Exploring Antimicrobial Potential of Hydrazones As Promising Lead
Available online a t www.derpharmachemica.com Scholars Research Library Der Pharma Chemica, 2011, 3(1):250-268 (http://derpharmachemica.com/archive.html) ISSN 0975-413X CODEN (USA): PCHHAX Therapeutic Review Exploring Antimicrobial Potential of Hydrazones as Promising Lead Goldie Uppal, Suman Bala*, Sunil Kamboj and Minaxi Saini M.M. College of Pharmacy, Maharishi Markandeshwar University, Ambala, Haryana, India ______________________________________________________________________________ ABSTRACT This review includes detailed study of structures of various hydrazones synthesized and evaluated for their antimicrobial activity. Hydrazone is a class of organic compounds with structure R 1R2C=NNH 2. Hydrazones containing an azomethine -NHN=CH- proton which leads to an important class of compounds for new drug development. Hydrazones are present in many of the bioactive heterocyclic compounds that are of very important use because of their various biological and clinical applications. Therefore, many researchers have synthesized these compounds as target structures and evaluated their antimicrobial activities. These observations have been guiding for the development of new hydrazones that possess varied biological activities. Key Words: Hydrazones, Hydrazide, Antifungal Activity, Antimicrobial Activity. ______________________________________________________________________________ INTRODUCTION The need to design new compounds to deal with the resistant strains has become one of the most important areas of research today. Hydrazone is a versatile moiety that exhibits a wide variety of biological activities. A hydrazone is a class of organic compounds with the structure R1R2C=NNH 2. Hydrazones are basically related to ketones and aldehydes. Hydrazones are formed by the replacement of the oxygen of carbonyl compounds with the -NNH 2 functional group. Hydrazones act as reactants in many important reactions e.g. -
5.2. Related Mechanisms of Halogen Chemistry a Large Variety of Organic
5.2. Related mechanisms of halogen chemistry A large variety of organic reactions involving different halogen species is known within the basic organic chemistry literature (e.g. March, 1992). Those reactions can be divided into two groups: carbon skeleton affecting and functionality modifying reactions. The halogen species discussed here are the species which are supposed to be present during the molecular halogen photochemical experiments: X2, HOX and HX, where X is chlorine or bromine. XO radicals formed by the rapid reactions of halogen atoms with ozone are considered to be unreactive against the organic precursors and to be converted to HOX via reaction with HO2, thus keeping the levels low (Mellouki et al., 1994; Bedjanian et al., 2001). The chosen precursors for the SOA represent different structural elements like an aliphatic structure with ring strain, comprising primary, secondary and tertiary C-H bonds, and an olefinic double bond (α- pinene) and substituted aromatic/phenolic structures (catechol and its methyl-ether modification guaiacol), where ring opening upon oxidation and possibly aldol condensation lead to further olefinic and conjugated structures. Those different organic precursors result in a different chemical structure of the related SOA. The SOA is considered to be still highly reactive and thus will offer a different chemical environment for RHS chemistry. The change of carbon-hydrogen bonds, observed by long-path FTIR spectroscopy upon halogenation (Fig. 4), can be related to the abstraction reaction of H atoms by chlorine atoms from C-H bonds of the methyl groups of the carbon structure (2A). (2A) Molecular chlorine might then react with the aliphatic radical in the well-known chain propagation of photochlorination according to equation (2B) in the initial phase of chlorine injection. -
2.1 the 18-ELECTRON RULE the 18E Rule1 Is a Way to Help Us Decide
30 GENERAL PROPERTIES OF ORGANOMETALLIC COMPLEXES 2.1 THE 18-ELECTRON RULE The 18e rule1 is a way to help us decide whether a given d-block transition metal organometallic complex is likely to be stable. Not all the organic formulas we can write down correspond to stable species. For example, CH5 requires a 5-valent carbon and is therefore not stable. Stable compounds, such as CH4,have the noble gas octet, and so carbon can be thought of as following an 8e rule. This corresponds to carbon using its s and three p orbitals to form four filled bonding orbitals and four unfilled antibonding orbitals. On the covalent model, we can consider that of the eight electrons required to fill the bonding orbitals, four come from carbon and one each comes from the four H substituents. We can therefore think of each H atom as being a 1e ligand to carbon. To assign a formal oxidation state to carbon in an organic molecule, we impose an ionic model by artificially dissecting it into ions. Each electron pair in any bond is assigned to the most electronegative of the two atoms or groups that constitute the bond. For methane, this dissection gives C4− + 4H+, with carbon as the more electronegative element. This makes methane an 8e compound with an oxidation state of −4, usually written C(-IV). Note that the net electron count always remains the same, whether we adopt the covalent (4e {Catom}+4 × 1e {4H atoms}=8e) or ionic (8e{C4−ion}+4 × 0e{4H+ions}=8e) model. -
Assessing the Feasibility of a One-Pot, Tandem Olefin Metathesis and Isomerization Sequence to Synthesize Conjugated Aromatic Olefins
University of Tennessee at Chattanooga UTC Scholar Student Research, Creative Works, and Honors Theses Publications 8-2016 Assessing the feasibility of a one-pot, tandem olefin metathesis and isomerization sequence to synthesize conjugated aromatic olefins Ajay D. Makwana University of Tennessee at Chattanooga, [email protected] Follow this and additional works at: https://scholar.utc.edu/honors-theses Part of the Chemistry Commons Recommended Citation Makwana, Ajay D., "Assessing the feasibility of a one-pot, tandem olefin metathesis and isomerization sequence to synthesize conjugated aromatic olefins" (2016). Honors Theses. This Theses is brought to you for free and open access by the Student Research, Creative Works, and Publications at UTC Scholar. It has been accepted for inclusion in Honors Theses by an authorized administrator of UTC Scholar. For more information, please contact [email protected]. Assessing the Feasibility of a One-Pot, Tandem Olefin Metathesis and Isomerization Sequence to Synthesize Conjugated Aromatic Olefins Ajay D. Makwana Departmental Honors Thesis The University of Tennessee at Chattanooga Department of Chemistry Project Director: Dr. Kyle S. Knight Examination Date: April 4, 2016 Members of Examination Committee: Dr. John P. Lee Dr. Han J. Park Dr. David Giles 1 Abstract The synthesis of substituted phenylpropene dimers using a one-pot, tandem olefin metathesis and isomerization sequence has been studied. This sequence relies on the facilitated, in-situ conversion of a ruthenium carbene species (Ru=C) to a ruthenium hydride species (Ru-H) upon addition of an inorganic hydride source. Three separate reactions occur within one reaction flask: 1) olefin metathesis of the starting phenylpropene to yield phenylpropene dimer via Ru=C catalyst, 2) conversion of Ru=C to Ru-H via addition of an inorganic hydride source, 3) isomerization of phenylpropene dimer via insertion and β-hydride elimination to yield conjugated product.