DOCSLIB.ORG

Stereochemistry

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Stereochemistry by Dr. Dorian Didier Office: F 3.080 [email protected] Lab: F 2.064 Dorian Didier Research Group DidierResearchGroup 1 0 Table of contents by D. Didier (LMU) 1 Introduction, definitions and reminders 2 Preparation of optically active molecules 3 Diastereoselective reactions 4 Enantioselective reactions 2 0 Table of contents by D. Didier (LMU) 1 Introduction, definitions and reminders 2 Preparation of optically active molecules 3 Diastereoselective reactions 4 Enantioselective reactions 3 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals 1.2 Isomerism 1.3 Definitions and reminders 1.4 Chirality 1.5 Absolute configurations 4 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals Steric vs. electronic effects Nonbonding interactions (Van der Waals repulsion) between Steric effects substituents within a molecule or between reacting molecules The effect of bond and through-space polarization by Electronic effects heteroatom substituents on reaction rates and selectivities Example: 1,4-addition Tet. 2000, 7715 (Yakura) Electronic effect: Steric effect: coordination repulsion 5 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals Stereoelectronic effects Stereoelectronic Geometrical constraints placed upon ground and transition effects states by orbital overlap considerations Anomeric effect s*(C-O) DG° = +0.6 kcal.mol-1 nO (filled sp3) DG° = -0.6 kcal.mol-1 6 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals Hybridization 1 x s + 3 x p 1 x s + 2 x p 1 x s + 1 x p s p p p s p p p s p p p sp3 sp3 sp3 sp3 sp2 sp2 sp2 p sp sp p p sp3 p p sp2 sp2 sp sp sp3 sp2 p sp3 sp3 tetrahedral planar linear 3 2 1 sp sp sp or sp 7 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals Resulting geometry sp3 sp2 sp 8 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals Orbital orientation s bonds p bonds antibonding s* p* bonding s p Nat. 2001, 539 (Weinhold) staggered eclipsed conformation s*C-H conformation LUMO sC-H s*C-H sC-H HOMO LUMO HOMO 9 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals study case: N2F2 LUMO LUMO HOMO HOMO s*N-F s*N-F nN nN s*N-F s*N-F Lone pair delocalization HOMO-LUMO appears to override delocalization is stronger electron-electron and in the cis isomer due dipole-dipole repulsion to better orbital overlap in the stabilization of nN nN the cis isomer the cis isomer is favored by 3 kcal/ mol at 25 °C 10 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals SN2 The Nu–C–X bonding interaction is that of a 3-center, 4-electron bond (3c4e). ∗ The frontier orbitals which are involved are the nonbonding orbital from Nu as well as σC–X and σ C–X 3c4e model Inversion Retention E LUMO s*C-X n HOMO N nN s*C-X HOMO LUMO s C-X Overlap from this Constructive overlap geometry results in no between Nu & σ* C–X net bonding interaction11 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals E2 synperiplanar antiperiplanar s C-H s*C-X s C-H s*C-X HOMO LUMO HOMO LUMO The interaction between s C-H and s*C-X leads to a conformation with H and X being trans-antiperiplanar 12 1 Introduction, definitions and reminders by D. Didier (LMU) 1.1 Frontier Molecular Orbitals electrophilic trapping inversion retention ACIE 2002, 717 (Basu) ACIE 2018, 5516 (Knochel) 13 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism – reminder Isomers are structures that possess the same chemical formula Isomers same connectivity? NO YES Constitutional Stereoisomers isomers 14 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Stereoisomerism Form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientations of their atoms in space Stereoisomers Through Through bond rotation bond cleavage Configurational Conformers isomers 15 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Conformers Natta Sägebock Newman projection projection projection eclipsed conformation E (kcal.mol-1) 3 0 j () 0 60 120 staggered conformation 16 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism n-butane E (kcal.mol-1) 4.5 3.6 gauche-conformation 0.9 0 dihedral angle 180° 120° 60° 0° (H3C-C-C-CH3) anti-conformation 17 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Conformers chair boat conformation conformation E (kcal.mol-1) half-chair 11 7 5.5 twisted-boat 0 18 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Relevance Important to understand Felkin-Anh models eclipsed staggered Important to understand Zimmermann-Traxler models chair 1 chair 2 19 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism hydrazine N2H4 The nonbonding lone pair orbitals in the gauche isomer should be destabilizing due to electron-electron repulsion. s s N-H s n *N-H *N-H anti- N conformation E s*N-H Hydrazine can exist in LUMO either gauche or anti conformations (relative to lone pairs) nN gauche- HOMO conformation s N-H 20 HOMO 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism hydrogen peroxide H2O2 Major stabilizing interaction is the delocalization of O-lone pairs into the C–H antibonding orbitals. There are no such stabilizing interactions in the anti-conformation while there are 2 in the gauche conformation. anti- E conformation H2O2 can exist in either s*O-H gauche or anti LUMO conformations (relative s*O-H to H atoms) n nO O HOMO gauche- conformation 21 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Esters – (E) or (Z)? ? (E)-conformation (Z)-conformation 22 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Esters – (E) or (Z)? ? (E)-conformation (Z)-conformation E (kcal.mol-1) 1 s*C-O 10-12 s*C-R LUMO LUMO nO HOMO nO HOMO 2-3 1 nO – s*C-O nO – s*C-R overlap overlap 1 σ*C–O is a better acceptor than σ*C-R (where R is a carbon substituent). Therefore the (E) conformation is stabilized by this interaction. 23 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Destabilizing effects eclipsed staggered repulsive interaction between πC-C & σC-H πC-C πC-C -1 E (kcal.mol ) σC-H σC-H 2 σC-H σC-H σC-H σC-H 0 JACS 1985, 5035 (Wiberg) JACS 1987, 6591 (Houk) 24 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems 1-butene E (kcal.mol-1) 1.32 0.49 0 j 25 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems 2-propen-1-ol E (kcal.mol-1) 2 1.18 0.37 0 j 26 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems 2-methyl-1-butene E (kcal.mol-1) 2.68 1.39 0.06 0 j 27 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems 2-methyl-2-propen-1-ol E (kcal.mol-1) 2.01 1.16 0.21 0 j 28 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems (Z)-2-pentene E (kcal.mol-1) 3.88 0.56 0 29 1 Introduction, definitions and reminders by D. Didier (LMU) 1.2 Isomerism Allylic systems (Z)-2-buten-1-ol E (kcal.mol-1) 1.44 0.86 0 30 1 Introduction, definitions and reminders by D. Didier (LMU) 1.3 Definitions Asymmetric synthesis Preparation of chiral molecules Point in a molecule bearing different substituents, Stereocenter such that interchanging any two of them or stereogenic center leads to a stereoisomer Molecule that possesses a non-superposable Chiral molecule mirror image 31 1 Introduction, definitions and reminders by D. Didier (LMU) 1.3 Definitions Configurational isomers are the molecules mirror images? NO YES Diasteoisomers Enantiomers 32 1 Introduction, definitions and reminders by D. Didier (LMU) 1.3 Definitions Mixture containing equal quantities of Racemic mixture both enantiomers Mixture containing different quantities of Enantioenriched mixture two enantiomers Enantiopure compound Mixture containing only one enantiomer 33 1 Introduction, definitions and reminders by D. Didier (LMU) 1.3 Definitions Enantiomeric excess Value representing the excess of one (ee) enantiomer over the second one n[(R)-A] – n[(S)-A] ee = 100 · 62% ee n[(R)-A] + n[(S)-A] n[(R)-A] er = er = 81:19 n[(S)-A] enantiomeric ratio Diastereomeric ratio (dr) dr = 93:7 dr = 95:3:1:1 34 1 Introduction, definitions and reminders by D. Didier (LMU) 1.3 Definitions A reaction that selectively leads to one or a series Stereoselectivite reaction of stereoisomers, disfavoring the other ones. This can be a result of competitive interactions. A reaction in which the stereochemical outcome is Stereospecific reaction guided by the mechanism. It requires a particular (specific) arrangement of the atoms (or functional groups) for the reaction to proceed. Stereospecific does not mean that only one stereoisomer is obtained. If a reaction gives only one diastereoisomer, it is fully diastereoselective.
Recommended publications
  • Download Author Version (PDF)

    Download Author Version (PDF)

    Chemical Science Accepted Manuscript This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/chemicalscience Page 1 of 4 PleaseChemical do not adjust Science margins Chemical Science EDGE ARTICLE Absolute Structure Determination of Compounds with Axial and Planar Chirality Using the Crystalline Sponge Method a a a b a Received 00th January 20xx, Shota Yoshioka, Yasuhide Inokuma, Manabu Hoshino, Takashi Sato, and Makoto Fujita* Accepted 00th January 20xx The absolute stereochemistry of compounds with axial and planar chirality is successfully determined by the crystalline DOI: 10.1039/x0xx00000x sponge method without crystallization or derivatization of the compounds. This method is applied to absolute structure determination in the asymmetric synthesis of unique compounds with axial and planar chirality.
  • Synthesis of Axially Chiral Biaryl Compounds by Asymmetric Catalytic Reactions with Transition Metals Pauline Loxq, E

    Synthesis of Axially Chiral Biaryl Compounds by Asymmetric Catalytic Reactions with Transition Metals Pauline Loxq, E

    Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals Pauline Loxq, E. Manoury, Rinaldo Poli, Éric Deydier, A. Labande To cite this version: Pauline Loxq, E. Manoury, Rinaldo Poli, Éric Deydier, A. Labande. Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals. Coordination Chemistry Re- views, Elsevier, 2016, 308, Part 2, pp.131-190. 10.1016/j.ccr.2015.07.006. hal-01929757 HAL Id: hal-01929757 https://hal.archives-ouvertes.fr/hal-01929757 Submitted on 1 Mar 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals Pauline Loxq, a,b Eric Manoury,a,b Rinaldo Poli,a,b,c Eric Deydier a,b,d,* and Agnès Labande a,b,* a CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France. b Université de Toulouse, UPS, INPT, F-31077 Toulouse Cedex 4, France. c Institut Universitaire de France, 103, bd Saint-Michel, 75005 Paris, France. d IUT A Paul Sabatier, Departement de Chimie, Avenue Georges Pompidou, CS 20258, F- 81104 Castres Cedex, France Dedicated to the memory of our colleague and friend Guy Lavigne (1947-2015).
  • Chapter 8. Chiral Catalysts José M

    Chapter 8. Chiral Catalysts José M

    Chapter 8. Chiral Catalysts José M. Fraile, José I. García, José A. Mayoral 1. The Origin of Enantioselectivity in Catalytic Processes: the Nanoscale of Enantioselective Catalysis. Enantiomerically pure compounds are extremely important in fields such as medicine and pharmacy, nutrition, or materials with optical properties. Among the different methods to obtain enantiomerically pure compounds, asymmetric catalysis1 is probably the most interesting and challenging, in fact one single molecule of chiral catalyst can transfer its chiral information to thousands or even millions of new chiral molecules. Enantioselective reactions are the result of the competition between different possible diastereomeric reaction pathways, through diastereomeric transition states, when the prochiral substrate complexed to the chiral catalyst reacts with the corresponding reagent. The efficiency of the chirality transfer, measured as enantiomeric excess [% ee = (R−S)/(R+S) × 100], depends on electronic and steric factors in a very subtle form. A simple calculation shows that differences in energy of only 2 kcal/mol between these transition states are enough to obtain more than 90% ee, and small changes in any of the participants in the catalytic process can modify significantly this difference in energy. Those modifications may occur in the near environment of the catalytic centre, at less than 1 nm scale, but also at longer distances in the catalyst, substrate, reagent, solvent, or support in the case of immobilized catalysts. This is the reason because asymmetric
  • [2.2]Paracyclophane-Based Bisoxazoline Ligands and Their

    [2.2]Paracyclophane-Based Bisoxazoline Ligands and Their

    molecules Communication PlanarCommunication Chiral [2.2]Paracyclophane-Based Bisoxazoline LigandsPlanar Chiral and Their [2.2]Paracyclophane-Based Applications in Cu-Mediated Bisoxazoline N–H InsertionLigands and Reaction Their Applications in Cu-Mediated N–H Insertion1, Reaction1, 1 2 1,3, Daniel M. Knoll y , Yuling Hu y, Zahid Hassan , Martin Nieger and Stefan Bräse * 1 DanielInstitute M. ofKnoll Organic 1,†, Yuling Chemistry Hu (IOC),1,†, Zahid Karlsruhe Hassan Institute 1, Martin of Nieger Technology 2 and (KIT), Stefan Fritz-Haber-Weg Bräse 1,3,* 6, 76131 Karlsruhe, Germany; [email protected] (D.M.K.); [email protected] (Y.H.); 1 [email protected] Institute of Organic Chemistry (Z.H.) (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 2 DepartmentKarlsruhe, Germany; of Chemistry, [email protected] University of Helsinki, (D.M.K.); P.O. [email protected] Box 55 A.I. Virtasen aukio (Y.H.); 1, 00014 Helsinki, Finland; martin.nieger@helsinki.fi[email protected] (Z.H.) 2 3 Institute Department of Toxicology of Chemistry, and University Genetics (ITG), of Helsinki, Karlsruhe P.O. InstituteBox 55 A.I. of Virtasen Technology aukio (KIT), 1, 00014 Helsinki, Hermann-von-Helmholtz-PlatzFinland; [email protected] 1, D-76344 Eggenstein-Leopoldshafen, Germany 3 * Correspondence: Institute of Toxicology [email protected]; and Genetics Tel.: (ITG),+49-7216-084-2902 Karlsruhe Institute of Technology (KIT), Hermann-von- TheseHelmholtz-Platz authors contributed 1, D-76344 equally Eggenstein-Leopoldshafen, to this work. Germany. y * Correspondence: [email protected]; Tel.: +49-7216-084-2902 † These authors contributed equally to this work.
  • Helicoselective Synthesis of Dioxa[6]Helicenes and Design of Orginal P-Stereogenic Brønsted Acid Organocatalystsx

    Helicoselective Synthesis of Dioxa[6]Helicenes and Design of Orginal P-Stereogenic Brønsted Acid Organocatalystsx

    Helicoselective Synthesis of Dioxa[6]helicenes and Design of Orginal P-Stereogenic Brønsted Acid Organocatalystsx. Peng Liu To cite this version: Peng Liu. Helicoselective Synthesis of Dioxa[6]helicenes and Design of Orginal P-Stereogenic Brøn- sted Acid Organocatalystsx.. Organic chemistry. Ecole Centrale Marseille, 2020. English. NNT : 2020ECDM0004. tel-03127048 HAL Id: tel-03127048 https://tel.archives-ouvertes.fr/tel-03127048 Submitted on 1 Feb 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N° BU: ……………….. THÈSE Helicoselective Synthesis of Dioxa[6]helicenes and Design of Original P-Stereogenic Brønsted Acid Organocatalysts Présentée par Peng LIU Pour obtenir le grade de Docteur en Sciences de l'Université Aix-Marseille Spécialité : Chimie Organique École Doctorale des Sciences Chimiques - ED 250 Institut des Sciences Moléculaires de Marseille (iSm2)-UMR 7313 Équipe Synthèse Totale et Réactivité Organique (STeRéO) Soutenue publiquement le 21 septembre 2020 devant la commission d’examen composée de : Dr Angela MARINETTI, Institut de Chimie des Substances Naturelles (ICSN) Rapporteur Pr Jieping ZHU, École Polytechnique Fédérale de Lausanne (EPFL) Rapporteur Pr José Luis VICARIO, University of the Basque Country Examinateur Pr. Alexandre MARTINEZ, Aix Marseille Université Examinateur Pr.
  • 2017 Zhang Separation.Pdf

    2017 Zhang Separation.Pdf

    Journal of Pharmaceutical Analysis 7 (2017) 156–162 Contents lists available at ScienceDirect Journal of Pharmaceutical Analysis journal homepage: www.elsevier.com/locate/jpa Original Research Article Separation of atropisomers by chiral liquid chromatography and MARK thermodynamic analysis of separation mechanism ⁎ Ling Zhanga, , Yue Hub, Elizabeth Galellab, Frank P. Tomasellab, William P. Fishb a Chemical and Synthetic Development, Bristol-Myers Squibb Co., New Brunswick, NJ 08903, USA b Drug Product Science and Technology, Bristol-Myers Squibb Co., New Brunswick, NJ 08903, USA ARTICLE INFO ABSTRACT Keywords: In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from both scientific and Atropisomer separation regulatory perspectives. The compound of interest contains two stereogenic axes due to the hindered rotation Chiral HPLC around the single bonds connecting the aryl groups, which results in four potential configurational isomers Thermodynamic parameters (atropisomers). The separation of the four atropisomers was achieved on a derivatized β-cyclodextrin bonded β-cyclodextrin stationary phase stationary phase. Further investigation showed that low temperature conditions, including sample preparation Chiral separation mechanism (−70 °C), sample storage (−70 °C), and chromatographic separation (6 °C), were critical to preventing interconversion. LC-UV-laser polarimetric analysis identified peaks 1 and 2 as a pair of enantiomers and peaks 3 and 4 as another. Thermodynamic analysis of the retention data indicated that the separation of the pairs of enantiomers is primarily enthalpy controlled as indicated by the positive slope of the van’tHuff plot. The difference in absolute Δ (Δ H), ranged from 2.20 kJ/mol to 2.42 kJ/mol. 1. Introduction rotation around the hindered axial bond [20].
  • A Tool for Chirality Control in Asymmetric Catalysis

    A Tool for Chirality Control in Asymmetric Catalysis

    Flexibility – A Tool for Chirality Control in Asymmetric Catalysis Raivis Žalubovskis Doctoral Thesis Stockholm 2006 Akademisk avhandling som med tillstånd av Kungl Tekniska Högskolan i Stockholm framlägges till offentlig granskning för avläggande av filosofie doktorsexamen i kemi med inrikting mot organisk kemi, måndagen den 27 november, kl 10.00 i sal F3, KTH, Lindstedtsvägen 26, Stockholm. Avhandlingen försvaras på engelska. Opponent är Professor Alexandre Alexakis, Université de Genève, Schweiz. ISBN 91-7178-491-8 ISRN KTH/IOK/FR--06/104--SE ISSN 1100-7974 TRITA-IOK Forskningsrapport 2006:104 © Raivis Zalubovskis Universitetsservice US AB, Stockholm Zalubovskis, R. 2006 ”Flexibility – A Tool for Chirality Control in Asymmetric Catalysis”, Organic Chemistry, KTH Chemical Science and Engineering, SE-100 44 Stockholm, Sweden. Abstract This thesis deals with the design and synthesis of ligands for asymmetric catalysis: palladium catalyzed allylic alkylations, and rho- dium and iridium catalyzed hydrogenations of olefins. Chirally flexible phosphepine ligands based on biphenyl were synthesized and their properties were studied. The rotation barrier for configurationally flexible phosphepines was determined by NMR spectroscopy. The ratio of the atropisomers was shown to depend on the group bound to phosphorus. Only complexes with two homochiral ligands bound to the metal center were observed upon complexation with Rh(I). It was shown that one diastereomer of the flexible ligand exhibits higher activity but lower selectivity than its diastereomer in the rhodium catalyzed hydrogenation of methyl α-acetamido- cinnamate. These ligands were also tested in nickel catalyzed silabora- tions. Chiral P,N-ligands with pseudo-C2 and pseudo-CS symmetry based on pyrrolidines-phospholanes or azepines-phosphepines were synthesized and studied in palladium catalyzed allylic alkylations.
  • Organic & Biomolecular Chemistry

    Organic & Biomolecular Chemistry

    Organic & Biomolecular Chemistry Accepted Manuscript This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/obc Page 1 of 4 Organic & Biomolecular Chemistry Journal Name RSCPublishing COMMUNICATION Stereogenic α-carbons determine the shape and topology of [13]-macrodilactones† Cite this: DOI: 10.1039/x0xx00000x Anniefer N. Magpusao, a Kelli Rutledge, a Brandon Q. Mercado, b Mark W. Manuscript Peczuh a * Received 00th January 2012, Accepted 00th January 2012 DOI: 10.1039/x0xx00000x www.rsc.org/ Accepted The synthesis and characterization of new [13]-macrodilactones substituted at stereogenic centers - to the carbonyl are O α O reported. When one center is substituted, it directs the topology 4 of the macrocycle; when two centers are substituted, both the 7 shape and the topology are influenced.
  • Graphical Representation of Stereochemical Configuration

    Graphical Representation of Stereochemical Configuration

    Pure Appl. Chem., Vol. 78, No. 10, pp. 1897–1970, 2006. doi:10.1351/pac200678101897 © 2006 IUPAC INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY CHEMICAL NOMENCLATURE AND STRUCTURE REPRESENTATION DIVISION* GRAPHICAL REPRESENTATION OF STEREOCHEMICAL CONFIGURATION (IUPAC Recommendations 2006) Prepared for publication by JONATHAN BRECHER CambridgeSoft Corporation, 100 CambridgePark Drive, Cambridge, MA 02140, USA *Developed by the Task Group for Graphical Representation Standards for Chemical Structure Diagrams: Chairman: W. Town (UK); Members: J. Brecher (USA), K. N. Degtyarenko (UK), H. Gottlieb (USA), R. M. Hartshorn (New Zealand), G. P. Moss (UK), P. Murray-Rust (UK), J. Nyitrai (Hungary), W. Powell (USA), A. Smith (USA), S. Stein (USA), K. Taylor (USA), A. Williams (USA), A. Yerin (Russia); Corresponding Members: S. Conway (UK), H. Cooke (USA), P. Giles (USA), M. Griffiths (USA), B. Košata (Czech Republic), B. Ramsay (USA). Comments and suggestions for future revisions of these recommendations may be sent to Jonathan Brecher ([email protected]) or to the Secretary of the Division. Membership of the Division Committee when this report was approved: President: A. D. McNaught (UK); Vice President: G. P. Moss (UK); Secretary: W. H. Powell (USA); Titular Members: T. Damhus (Denmark), R. M. Hartshorn (New Zealand), H. D. Kaesz (USA), J. Kahovec (Czech Republic), J. Nyitrai (Hungary), A. Williams (USA), A. Yerin (Russia); Associate Members: J. Brecher (USA), S. Heller (USA), M. Hess (Germany), A. J. Lawson (Germany), G. J. Leigh (UK), M. Toussant (USA); National Representatives: R. Hoyos de Rossi (Argentina), L. F. Lindoy (Australia), R. de Barros Faria (Brazil), J. He (China), P. Righi (Italy), C. S.
  • A Chirality-Based Quantum Leap: a Forward-Looking Review Arxiv

    A Chirality-Based Quantum Leap: a Forward-Looking Review Arxiv

    A Chirality-Based Quantum Leap: A Forward-Looking Review Clarice D. Aiello,∗,y,z Muneer Abbas,{ John Abendroth,x Amartya S. Banerjee,k,y David Beratan,? Jason Belling,y,# Bertrand Berche,@ Antia Botana,4 Justin R. Caram,# Luca Celardo,r Gianaurelio Cuniberti,yy Arezoo Dianat,yy Yuqi Guo,zz Rafael Gutierrez,yy Carmen Herrmann,{{ Josh Hihath,xx Suneet Kale,kk Philip Kurian,?? Ying-Cheng Lai,## Ernesto Medina,@@ Vladimiro Mujica,kk Ron Naaman,44 Mohammadreza Noormandipour,y,z Julio Palma,rrr Yossi Paltiel,y y y William Petuskey,kk Jo~aoCarlos Ribeiro-Silva,z z z Dominik Stemer,y,k Ana Valdes-Curiel,y,z Solmar Varela,{{{ David Waldeck,xxx Paul S. Weiss,y,k Helmut Zacharias,kkk and Qing Hua Wang∗,zz E-mail: [email protected]; [email protected] y California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA, 90095 z Department of Electrical and Computer Engineering, University of California, Los An- geles, Los Angeles, CA, USA, 90095 arXiv:2009.00136v1 [cond-mat.mes-hall] 31 Aug 2020 { Department of Microbiology, Howard University, Washington, DC, USA, 20059 x Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA, 94305 k Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA, 90095 1 ? Department of Chemistry, Duke University, Durham, NC, USA, 27708 # Department of Chemistry & Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA, 90095 @ Laboratoire de Physique et Chimie Thoriques, UMR Universit´ede Lorraine-CNRS,
  • Stereoismerism Jeannecrassou

    Stereoismerism Jeannecrassou

    CHIRASKOOL Jeanne Crassous Phosphore et Matériaux Moléculaires http://pmm.univ-rennes1.fr/ Institut des Sciences Chimiques de Rennes UMR CNRS 6226 Université Rennes1, Av. du Général Leclerc 35042 C Rennes Cedex, France, H I [email protected] R A F U N Historical aspects and properties of enantiomers Definitions Symmetry aspects Symmetry point groups for achiral molecules Symmetry point groups for chiral molecules Molecules with stereogenic centers Asymmetric carbon, chiral amines, sulfoxides, phosphines, … Half-sandwich complexes, metallocenes Tetrahedral or spiro-type complexes Octahedral Complexes Molecules displaying axial chirality Examples of allenes Atropoisomerism and axial chirality Planar chirality Inherent chirality Helicenes, fullerenes Trefoil knots and topological chirality Selected examples: stereochemistry of helicene derivatives Some (simplified) history… Bartholin (1669) birefringence Iceland Spar – Spath d’Islande (CaCO3) Malus (1808) Polarization of light Direction of propagation Wave seen Polarization plane by the observer Abbey Haüy (1809) modern crystallography, hemihedry Mitscherlich (1819) polymorphism Arago (1811) Herschel (1820) Hemihedral crystals of quartz They ‘turn the light’ : they have a rotatory power The Biot’s polarimeter (1815) Solutions of camphor, glucose, tartaric acid They ‘turn the light’ : they have a rotatory power (optical rotation) Camphor tree Grapes (tartaric acid) The tartrates by Pasteur (1848) 1820 Kessler (Alsacian chemist) Synthesis of a mysterious acid after refining the
  • Planar Chiral Lewis Acids and Lewis Pairs Based On

    Planar Chiral Lewis Acids and Lewis Pairs Based On

    PLANAR CHIRAL LEWIS ACIDS AND LEWIS PAIRS BASED ON FERROCENE by JIAWEI CHEN A Dissertation submitted to the Graduate School-Newark Rutgers, The State University of New Jersey in partial fulfillment of requirements for the degree of Doctor of Philosophy Graduate Program in Chemistry written under the guidance of Professor Frieder Jäkle and approved by Newark, New Jersey May, 2014 © 2014 Jiawei Chen ALL RIGHTS RESERVED ABSTRACT OF THE DISSERTATION PLANAR CHIRAL LEWIS ACIDS AND LEWIS PAIRS BASED ON FERROCENE by Jiawei Chen Dissertation Advisor: Professor Frieder Jäkle Organoboranes have been widely used for catalytic transformations, polymerizations, small molecule activation, anion and glycol sensing and construction of electronic materials. These remarkable applications commonly benefit from the electron-deficient nature of tricoordinate boron, i.e., its empty p- orbital can accommodate a lone pair of electrons or participate in conjugation of extended π-systems. Therefore, approaches to enhance the Lewis acidity of the boron center are desirable, and different strategies have been introduced with this aim, including (1) installation of electron withdrawing pendant groups such as pentafluorophenyl groups; (2) generation of cationic borenium species and (3) incorporation of tricoordinate boron into anti-aromatic systems such as borole derivatives. Recently, much effort has been directed to the preparation of the so- called “Frustrated Lewis Pair” (FLP) and the application of their unquenched relativity for catalytic transformations. However, chiral versions of highly Lewis acidic organoboranes remain scarce. On the other hand, planar chiral ferrocenes have proven to provide rigid frameworks for transition metal ligands such as ii phosphines and amines, which have been successfully applied to the asymmetric hydrogenation of alkenes, ketones and other processes.