Functionalized Organolithium Compounds: New Synthetic Adventures
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Superhalogen and Superacid. Superalkali and Superbase
Superhalogen and Superacid. Superalkali and Superbase Andrey V. Kulsha,1 Dmitry I. Sharapa2,3 Correspondence to: Andrey V. Kulsha [email protected]; Dmitry I. Sharapa [email protected] 1 Andrey V. Kulsha Lyceum of Belarusian State University, 8 Ulijanauskaja str., Minsk, Belarus, 220030 2 Dmitry I. Sharapa Chair of Theoretical Chemistry and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universitat Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany 3 Institute of Catalysis Research and Technology (IKFT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Germany, D-76344 ABSTRACT A superhalogen F@C20(CN)20 and a superalkali NC30H36 together with corresponding Brønsted superacid and superbase were designed and investigated on DFT and DLPNO-CCSD(T) levels of theory. Calculated compounds have outstanding properties (electron affinity, ionization energy, deprotonation energy, and proton affinity, respectively). We consider superacid H[F@C20(CN)20] to be able to protonate molecular nitrogen, while NC30H35 superbase should easily deprotonate SiH4. Neutral NC30H36 should form a metallic metamaterial with extreme properties like remarkable transparency to visible light due to infrared plasmonic wavelength. The stability of these structures is discussed, while some of the previous predictions concerning Brønsted superacids and superbases of record strength are doubted. The proton affinity limit was suggested for stable neutral Brønsted superbases. Introduction Traditionally, a superhalogen is a molecule with However, few of the known superhalogen and high electron affinity, which forms a stable superalkali neutral molecules are stable in 5-7 anion. A good example is AuF6 with electron condensed phase. For example, some anions affinity of about 8.2 eV.1 Just in the same way a were predicted to have vertical electron superalkali is a molecule with low ionization detachment energies above 13 eV,8,9 but the energy, which forms a stable cation. -
United States Patent (19) 11 Patent Number: 6,057,352 Brown Et Al
US006057352A United States Patent (19) 11 Patent Number: 6,057,352 Brown et al. (45) Date of Patent: May 2, 2000 54 FUNGICIDAL CYCLIC AMIDES WO 96/17851 6/1996 WIPO ............................... CO7F 7/08 WO 96/26.191 8/1996 WIPO ... ... CO7D 249/12 75 Inventors: Richard James Brown, Newark, Del.: WO 96/36633 11/1996 WIPO ... ... CO7D 405/04 Deborah Ann Frasier, Martinez, Calif.; WO96/36229 11/1996 WIPO ... ... A01N 43/653 Michael Henry Howard, Jr., WO 97/02255 1/1997 WIPO m CO7D 261/12 Rockland; Gerard Michael Koether, OTHER PUBLICATIONS Bear, both of Del. Zvilichovsky, G., J. Heterocyclic Chem., 24,465–470, 1987. 73 Assignee: E. I. du Pont de Nemours and Zvilichovsky, G. et al., J. Heterocyclic Chem., 25, Company, Wilmington, Del. 1307-1310, 1988. Davis, M. et al., Australian J. Chem., 30(8), 1815-1818, 21 Appl. No.: 08/952,380 1977. 22 PCT Filed: May 8, 1996 Primary Examiner Mukund J. Shah 86 PCT No.: PCT/US96/06534 Assistant Examiner Deepak R. Rao S371 Date: Nov. 13, 1997 57 ABSTRACT S 102(e) Date: Nov. 13, 1997 Compounds of Formula (I), 87 PCT Pub. No.: WO96/36616 (I) PCT Pub. Date: Nov. 21, 1996 1.Y. Nz Related U.S. Application Data x - W 63 Continuation-in-part of application No. 08/442,433, May NY 17, 1995, abandoned. A-N 60 Provisional application No. 60/004,183, Sep. 22, 1995. Ye 51) Int. Cl." ...................... C07D 249/12; CO7D 233/30; AO1N 43/74; AO1N 43/56 and their N-oxides and agriculturally Suitable Salts are 52 U.S. -
S41467-018-04983-2.Pdf
ARTICLE DOI: 10.1038/s41467-018-04983-2 OPEN Novofumigatonin biosynthesis involves a non- heme iron-dependent endoperoxide isomerase for orthoester formation Yudai Matsuda 1,2,3, Tongxuan Bai2, Christopher B.W. Phippen1, Christina S. Nødvig1, Inge Kjærbølling1, Tammi C. Vesth1, Mikael R. Andersen 1, Uffe H. Mortensen 1, Charlotte H. Gotfredsen 4, Ikuro Abe 2 & Thomas O. Larsen 1 1234567890():,; Novofumigatonin (1), isolated from the fungus Aspergillus novofumigatus, is a heavily oxy- genated meroterpenoid containing a unique orthoester moiety. Despite the wide distribution of orthoesters in nature and their biological importance, little is known about the biogenesis of orthoesters. Here we show the elucidation of the biosynthetic pathway of 1 and the identification of key enzymes for the orthoester formation by a series of CRISPR-Cas9-based gene-deletion experiments and in vivo and in vitro reconstitutions of the biosynthesis. The novofumigatonin pathway involves endoperoxy compounds as key precursors for the orthoester synthesis, in which the Fe(II)/α-ketoglutarate-dependent enzyme NvfI performs the endoperoxidation. NvfE, the enzyme catalyzing the orthoester synthesis, is an Fe(II)- dependent, but cosubstrate-free, endoperoxide isomerase, despite the fact that NvfE shares sequence homology with the known Fe(II)/α-ketoglutarate-dependent dioxygenases. NvfE thus belongs to a class of enzymes that gained an isomerase activity by losing the α- ketoglutarate-binding ability. 1 Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark. 2 Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. 3 Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China. -
Publikationsliste Internet
Professor Dr. Alois Fürstner List of Publications 2020 F. Caló, A. Fürstner A Heteroleptic Dirhodium Catalyst for Asymmetric Cyclopropanation with -Stannyl -Diazoacetate. ‘Stereoretentive’ Stille Coupling with Formation of Chiral Quarternary Carbon Centers Angew. Chem. 2020, 132; 14004-14011, Angew. Chem. Int. Ed. 2020, 59, 13900-13907 H. Jin, A. Fürstner Modular Synthesis of Furans with up to Four Different Substituents by a trans‐Carboboration Strategy Angew. Chem. 2020, 132; 13720-13724, Angew. Chem. Int. Ed. 2020, 29, 1316-13622 Z. Meng, A. Fürstner Total Synthesis Provides Strong Evidence: Xestocyclamine A is the Enantiomer of Ingenamine J. Am. Chem. Soc. 2020, 142, 11703-11708 J. Hillenbrand, M. Leutzsch, E. Yiannakas, C. Gordon, C. Wille, N. Nöthling, C. Copéret, A. Fürstner “Canopy Catalysts” for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework J. Am. Chem. Soc.2020, 142, 11279-11294 M. Heinrich, J. Murphy, M. Ilg, A. Letort, J. Flasz, P. Philipps, A. Fürstner Chagosensine: A Riddle Wrapped in a Mystery Inside an Enigma J. Am. Chem. Soc. 2020, 142, 6409-6422 M. Buchsteiner, L. Martinez-Rodriguez, P. Jerabek, I. Pozo, M. Patzer, N. Nöthling, C. Lehmann, A. Fürstner Catalytic Asymmetric Fluorination of Copper Carbene Complexes: Preparative Advances and a Mechanistic Rationale Chem.–Eur. J. 2020, 26, 2509-2515 2019 S. Peil, A. Fürstner Mechanistic Divergence in the Hydrogenative Synthesis of Furans and Butenolides: Ruthenium Carbenes Formed by gem-Hydrogenation or via Carbophilic Activation of Alkynes Angew. Chem. 2019, 131; 18647-18652; Angew. Chem. Int. Ed. 2019, 58, 18476-18481 L. Huang, Y. Gu, A. Fürstner Iron Catalyzed Reactions of 2-Pyridone Derivatives: 1,6-Addition and Formal Ring Opening/Cross Coupling Chem. -
Synthetic Strategies to Access Biologically Important Fluorinated Motifs: Fluoroalkenes and Difluoroketones by Ming-Hsiu Yang Su
Synthetic Strategies to Access Biologically Important Fluorinated Motifs: Fluoroalkenes and Difluoroketones By Ming-Hsiu Yang Submitted to the graduate degree program in Medicinal Chemistry and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Doctor of Philosophy Chairperson Ryan A. Altman Michael D. Clift Apurba Dutta Michael F. Rafferty Jon A. Tunge Date Defended: April 26, 2017 The Dissertation Committee for Ming-Hsiu Yang certifies that this is the approved version of the following dissertation: Synthetic Strategies to Access Biologically Important Fluorinated Motifs: Fluoroalkenes and Difluoroketones Chairperson Ryan A. Altman Date Approved: April 26, 2017 ii Abstract Ming-Hsiu Yang Department of Medicinal Chemistry, April 2017 The University of Kansas Fluorine plays an important role in drug design, because of some unique features imparted by fluorine. The incorporation of fluorine into small molecules can modulate molecular physicochemical properties, metabolic stability, lipophilicity, and binding affinity to the target proteins. However, few fluorinated molecules are biosynthesized by enzymes. This means incorporating fluorine into the molecules relies on synthetic methods. Thus, efficient synthetic strategies to access the molecules bearing a variety of privileged fluorinated moieties are important for drug discovery. Fluoroalkenes are an isopolar and isosteric mimic of an amide bond with distinct biophysical properties, including decreased H-bond donating and accepting abilities, increased lipophilicity, and metabolic stability. Moreover, fluoroalkenes can also serve as probes for conducting conformational analyses of amides. These potential applications require the development of efficient methods to access fluoroalkenes. In chapter 2, a Shapiro fluorination strategy to access peptidomimetic fluoroalkenes is demonstrated. -
Unexpected Barbier-Grignard Allylation of Aldehydes With
9102 J. Am. Chem. Soc. 1998, 120, 9102-9103 Unexpected Barbier-Grignard Allylation of Grignard allylation of aldehydes (1) with magnesium and allyl Aldehydes with Magnesium in Water halides (2) proceeds smoothly in water (eq 1). Chao-Jun Li* and Wen-Chun Zhang Department of Chemistry, Tulane UniVersity New Orleans, Louisiana 70118 ReceiVed March 26, 1998 To start our investigation, we reacted allyl bromide with benzaldehyde and magnesium turnings in 0.1 N aqueous HCl for An important step in the history of modern chemistry was the 3 h at room temperature. TLC analysis of the ether extract clearly introduction of magnesium for carbon-carbon bond formations1 2 showed a spot that corresponds to the desired allylation product. by Barbier and Grignard about a century ago, through the addition Subsequently, 1H NMR measurement of the crude reaction of an organometallic reagent to a carbonyl group. The study of mixture showed about 28% of the allylation product (3), together magnesium-based reactions since then has sparked the develop- with 66% of the pinacol coupling product (4),11 and 6% benzyl ment of new reagents based on electronically more negative and alcohol. This promising result prompted us to examine factors more positive metals as well as semi-metallic elements for various that influence the reaction. We then examined in greater detail synthetic purposes to tailor reactivities and selectivities (chemo, 3 the effect of the solvent system on the magnesium reaction by regio, and stereo). For carbonyl additions based on organomag- using various combinations of water and THF as the reaction nesium reagents, it is generally accepted that strict anhydrous 4 solvent together with a small amount of iodine to initiate the reaction conditions are required for a smooth reaction. -
Aldehydes Can React with Alcohols to Form Hemiacetals
340 14 . Nucleophilic substitution at C=O with loss of carbonyl oxygen You have, in fact, already met some reactions in which the carbonyl oxygen atom can be lost, but you probably didn’t notice at the time. The equilibrium between an aldehyde or ketone and its hydrate (p. 000) is one such reaction. O HO OH H2O + R1 R2 R1 R2 When the hydrate reverts to starting materials, either of its two oxygen atoms must leave: one OPh came from the water and one from the carbonyl group, so 50% of the time the oxygen atom that belonged to the carbonyl group will be lost. Usually, this is of no consequence, but it can be useful. O For example, in 1968 some chemists studying the reactions that take place inside mass spectrometers needed to label the carbonyl oxygen atom of this ketone with the isotope 18 O. 16 18 By stirring the ‘normal’ O compound with a large excess of isotopically labelled water, H 2 O, for a few hours in the presence of a drop of acid they were able to make the required labelled com- í In Chapter 13 we saw this way of pound. Without the acid catalyst, the exchange is very slow. Acid catalysis speeds the reaction up by making a reaction go faster by raising making the carbonyl group more electrophilic so that equilibrium is reached more quickly. The the energy of the starting material. We 18 also saw that the position of an equilibrium is controlled by mass action— O is in large excess. -
Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems
Electronic Supplementary Material (ESI) for Chemical Science. This journal is © The Royal Society of Chemistry 2014 Supporting Information Orthoester Exchange: a Tripodal Tool for Dynamic Covalent and Systems Chemistry René-Chris Brachvogel and Max von Delius* Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Henkestr. 42, 91054 Erlangen, Germany. * Fax: +49 9131 85 26864; Tel: +49 9131 85 22946; E-mail: [email protected] Contents General experimental section ....................................................................................................................S2 Reversibility of equilibration .....................................................................................................................S7 Investigation of solvents ...........................................................................................................................S11 Investigation of different orthoesters......................................................................................................S13 Investigation of different alcohols ...........................................................................................................S15 Treatment with bicarbonate solution .....................................................................................................S21 Analysis by GC-FID and HPLC-MS ......................................................................................................S23 Manipulation of equilibrium distribution ..............................................................................................S26 -
Shapiro Reaction
MANA TV programme SHAPIRO REACTION P. Kiran Kumar Lecturer in Chemistry SGA Government Degree College Yellamanchili SHAPIRO REACTION Treatment of tosyl hydrazone of an aldehyde or a ketone with a strong base leads to the formation of vinyl anion which on hydrolysis given an olefin. Hydrazine Phenyl Hydrazine Tosyl hydrazide (p-Toluenesulfonyl hydrazide) Tosyl hydrazone Formed by Nucleophilic addition between aldehyde or ketone and Tosyl hydrazide (p-Toluenesulfonyl hydrazide) and subsequent loss of carbonyl oxygen Mechanism Deprotonation of Tosyl hydrazone with a strong base to form Hydrazone aza enolate. Elimination of aryl sulfinate gives an unstable anion. Loss of Nitrogen leads to vinyl anion Hydrazone aza enolate unstable anion Vinyl anion Vinyl anions can be trapped by number various electrophiles 1. Hydrolysis gives an Alkene 2. Reaction with D2O gives Deuterated Alkene 3. Reaction with CO2 gives α, β-unsaturated acid 4. Reaction with formaldehyde gives Primary alcohol Vinyl anionsanions can can be be trapped trapped by by number number various various electrophiles – –Cont’dCont’d 5. Reaction with DMF gives an α, β-unsaturated aldehyde 6. Reaction with Alkyl chloride gives an Alkyl substituted alkene 7. Reaction with (CH3)3SiCl gives a Vinyl Silane Shapiro reaction involving cyclic ketones Cyclohexanone Shapiro reaction involving cyclic ketones Mechanism Mechanisms Mechanisms Mechanism Shapiro reaction involving unsymmetrical ketones unsymmetrical ketones gives predominantly less substituted olefins Shapiro reaction involving unsymmetrical ketones Removal of proton from the more substituted carbon atom Not formed Stability of the carbanion: secondary versus tertiary Secondary carbanion Tertiary carbanion Secondary carbanion more stable than primary carbanion. -
Syllabus CHEM 6352 2014
CHEM 6352 Organic Reactions & Synthesis Fall 2014 Jeremy A. May Office: 5025 SERC Office hours: T/Th 10-11 am or by appointment (email me) Email: [email protected] Website: http://mynsm.uh.edu/groups/maygroup/wiki/b24dc/Classes.html Lectures: 154 Fleming Tuesdays and Thursdays 8:30–10:00. August 26–December 6, 2014. Homework Session Saturdays 3:00 pm to 5:30 pm in Fleming 154/160/162. No class November 27–29, 2014 (Thanksgiving recess); Oct. 31st is last day to withdraw Optional Texts (on reserve at MD Anderson Library) Zweifel, G.; Nantz, M. “Modern Organic Synthesis: An Introduction” March, J. “Advanced Organic Chemistry” Corey, E. J.; Cheng, X.-M. “The Logic of Chemical Synthesis” Warren, S. “Designing Organic Syntheses: A Programmed Introduction to the Synthon Approach” Kürti, L.; Czakó, B. “Strategic Applications of Named Reactions in Organic Synthesis” Grossman, R. “The Art of Writing Reasonable Organic Reaction Mechanisms” Model Sets: Students are strongly encouraged to purchase at least one set. HGS biochemistry molecular model sets are recommended and are available at Research Stores in the Old Science Building. Other relevant texts and references: Greene; Wuts. “Protective Groups in Organic Synthesis” Nicolaou, K.C.; Sorensen, E. “Classics in Total Synthesis” Nicolaou, K.C.; Snyder, S. “Classics in Total Synthesis II” Larock, R. C. "Comprehensive Organic Transformations" Hartwig, J. “Organotransition Metal Chemistry: From Bonding to Catalysis” Tsuji, J. “Palladium Reagents and Catalysts” Hegedus, L. “Transition Metals in the Synthesis of Complex Organic Molecules” Problem Sets: Problem Sets will be distributed on Tuesdays (or before) and are due by the next Saturday at the Homework Session. -
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. -
The Effects of Stoichiometry and Starting Material on the Product Identity and Yield in Grignard Addition Reactions
Supplementary information for Comprehensive Organic Chemistry Experiments for the Laboratory Classroom © The Royal Society of Chemistry 2017 The effects of stoichiometry and starting material on the product identity and yield in Grignard addition reactions Supplementary Material This experiment has been performed both in the 150 person standard introductory organic chemistry laboratory (taught primarily by undergraduate teaching assistants in five sections of 30-40 students) and in a special introductory organic chemistry laboratory for freshman, taught to 23 students in sections of 7 and 16. This course is the first organic laboratory for these students but has been taught in the spring semester along with the second semester of organic lecture. The lab periods for this course are five hours long, and this experiment is typically performed in the latter half of the semester. This experiment is used to illustrate to students the importance of planning their time in lab; they must be out of the lab in the 5 hours allotted. While many students finish the experiment in this time, others plan to finish the following week along with a shorter experiment. Those who were running behind were encouraged to finish through the drying of their organic layer with MgSO4 and set up the distillation the following week. When doing this they should make sure that their organic layer is in a closed container to prevent evaporation of their product. Moisture Sensitive Conditions There are many diverse protocols for maintaining the anhydrous conditions required to successfully prepare and utilize Grignard reagents. We typically open a fresh can of anhydrous ether and dispense it directly, without additional drying in a still or air sensitive techniques for solvent transfers.