Chapter 8. Chiral Catalysts José M
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Enantiotopicity, Diastereotopicity
Stereochemistry and stereocontrolled synthesis (OC 8) A lecture from Prof. Paul Knochel, Ludwig-Maximilians-Universität München WS 2015-16 1 Wichtig! • Prüfung Stereochemistry 02. Februar 2016 8:00 – 10:00 Willstätter-HS • Nachholklausur Stereochemistry 5. April 2016 9:00 – 11:00 Willstätter-HS 2 Problem set part I 3 Problem set part II 4 Problem set part III 5 Recommended Literature • E. Juaristi, Stereochemistry and Conformational Analysis, Wiley, 1991. • E. Eliel, Stereochemistry of Organic Compounds, Wiley, 1994. • A. Koskinen, Asymmetric Synthesis of Natural Products, Wiley, 1993. • R. Noyori, Asymmetric Catalysis, Wiley, 1994. • F. A. Carey, R. J. Sundberg, Advanced Organic Chemistry, 5th Edition, Springer, 2007. • A. N. Collins, G. N. Sheldrake, J. Crosby, Chirality in Industrie, Vol. I and II, Wiley, 1995 and 1997. • G.Q. Lin, Y.-M. Li, A.S.C. Chan, Asymmetric Synthesis, 2001, ISBN 0-471-40027-0. • P. Deslongchamps, Stereoelectronic Effects in Organic Chemistry, Pergamon, 1983. • M. Nogradi, Stereoselective Synthesis, VCH, 1995. • E. Winterfeldt, Stereoselective Synthese, Vieweg, 1988. • R. Mahrwald (Ed.), Modern Aldol Reactions, Vol. I and II, Wiley, 2004. • C. Wolf, Dynamic Stereochemistry of Chiral Compounds, RSC Publishing, 2008. • A. Berkessel, H. Gröger, Asymmetric Organocatalysis, Wiley-VCH, 2005. • J. Christoffers, A. Baro (Eds.), Quaternary Stereocenters, Wiley-VCH, 2005. • Catalytic Asymmetric Synthesis, I. Oshima (Ed.), Wiley, 2010. 6 Recent advances of asymmetric catalysis 7 Asymmetric Hydrogenation of Heterocyclic Compounds 8 R. Kuwano, N. Kameyama, R. Ikeda, J. Am. Chem. Soc. 2011, 133, 7312-7315. Camphor-Derived Organocatalytic Synthesis of Chromanones 9 Z.-Q. Rong, Y. Li, G.-Q. Yang, S.-L. You, Synlett 2011, 1033-1037. -
Chiral Auxiliaries and Optical Resolving Agents
Chiral Auxiliaries and Optical Resolving Agents Most bioactive substances are optically active. For instance, if This brochure introduces a variety of chiral auxiliaries and a substance is synthesized as a racemic compound, its optical resolving agents. We hope that it will be useful for your enantiomer may show no activity or even undesired bioactivity. research of the synthesis of optically active compounds. Thus, methods to gain enantiopure compounds have been Additionally, TCI has some brochures introducing chiral developed. When synthesizing enantiopure compounds, the compounds for the chiral pool method in “Chiral Building Blocks”, methods are roughly divided into three methods. “Terpenes”, “Amino Acids” and other brochures. Sugar derivatives are also introduced in a catalog, “Reagents for Glyco Chemistry Chiral pool method: & Biology”, and category pages of sugar chains. Furthermore, The method using an easily available chiral compound as a TCI has many kinds of catalysts for asymmetric synthesis and starting material like an amino acid or sugar. introduce them in brochures such as “Asymmetric Synthesis” and Asymmetric synthesis: “Asymmetric Organocatalysts”, and other contents. The method to introduce an asymmetric point to compounds You can search our information through “asymmetric synthesis” without an asymmetric point. Syntheses using achiral as a keyword. auxiliaries are included here. Optical resolution: The method to separate a racemic compound into two ● Reactions with Chiral Auxiliaries enantiomers. The direct method using a chiral column and One of the most famous named reactions using chiral auxiliaries1) the indirect method to separate two enantiomers using is the Evans aldol reaction.2) This reaction is quite useful because optical resolving agents to convert into diastereomers are this reaction can efficiently introduce two asymmetric carbons into examples. -
A Reminder… Chirality: a Type of Stereoisomerism
A Reminder… Same molecular formula, isomers but not identical. constitutional isomers stereoisomers Different in the way their Same connectivity, but different atoms are connected. spatial arrangement. and trans-2-butene cis-2-butene are stereoisomers. Chirality: A Type of Stereoisomerism Any object that cannot be superimposed on its mirror image is chiral. Any object that can be superimposed on its mirror image is achiral. Chirality: A Type of Stereoisomerism Molecules can also be chiral or achiral. How do we know which? Example #1: Is this molecule chiral? 1. If a molecule can be superimposed on its mirror image, it is achiral. achiral. Mirror Plane of Symmetry = Achiral Example #1: Is this molecule chiral? 2. If you can find a mirror plane of symmetry in the molecule, in any achiral. conformation, it is achiral. Can subject unstable conformations to this test. ≡ achiral. Finding Chirality in Molecules Example #2: Is this molecule chiral? 1. If a molecule cannot be superimposed on its mirror image, it is chiral. chiral. The mirror image of a chiral molecule is called its enantiomer. Finding Chirality in Molecules Example #2: Is this molecule chiral? 2. If you cannot find a mirror plane of symmetry in the molecule, in any conformation, it is chiral. chiral. (Or maybe you haven’t looked hard enough.) Pharmacology of Enantiomers (+)-esomeprazole (-)-esomeprazole proton pump inhibitor inactive Prilosec: Mixture of both enantiomers. Patent to AstraZeneca expired 2002. Nexium: (+) enantiomer only. Process patent coverage to 2007. More examples at http://z.umn.edu/2301drugs. (+)-ibuprofen (-)-ibuprofen (+)-carvone (-)-carvone analgesic inactive (but is converted to spearmint oil caraway oil + enantiomer by an enzyme) Each enantiomer is recognized Advil (Wyeth) is a mixture of both enantiomers. -
Enantiotopic Discrimination in the NMR Spectrum of Prochiral Solutes in Chiral Liquid Crystals
Chemical Society Reviews Enantiotopic Discrimination in the NMR Spectrum of Prochiral Solutes in Chiral Liquid Crystals Journal: Chemical Society Reviews Manuscript ID: CS-REV-07-2014-000260 Article Type: Review Article Date Submitted by the Author: 29-Jul-2014 Complete List of Authors: Lesot, Phillippe; Universite Paris Sud (Paris XI), LRMN, ICMMO, UMR 8182 Aroulanda, Christie; Universite Paris Sud (Paris XI), LRMN, ICMMO, UMR 8182 Zimmermann, Herbert; Abteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Luz, Zeev; Weizmann Institute of Science, Department of Chemical Physics Page 1 of 117 Chemical Society Reviews Chem. Soc. Rev. (2014) - 1 - Enantiotopic Discrimination in the NMR Spectrum of Prochiral Solutes in Chiral Liquid Crystals Philippe Lesot* ,a , Christie Aroulanda a, Herbert Zimmermann b and Zeev Luz c a Laboratoire de RMN en Milieu Orienté CNRS UMR 8182, ICMMO, Bât. 410, Université de Paris-Sud, 91405 Orsay cedex, France. bAbteilung Biophysik, Max-Planck-Institut für Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany. c Weizmann Institute of Science, Department of Chemical Physics, Rehovot 76100, Israel. Corresponding author : Philippe Lesot: [email protected] Keywords : Prochirality, Enantiotopic sites, NMR, Chiral Liquid Crystals, Dynamics. Type of article : (comprehensive) review Chemical Society Reviews Page 2 of 117 Chem. Soc. Rev. (2014) - 2 - Abstract The splitting of signals in the NMR spectra originating from enantiotopic sites in prochiral molecules when dissolved in chiral solvents is referred to as spectral enantiotopic discrimination. The phenomenon is particularly noticeable in chiral liquid crystals (CLC) due to the combined effect of the anisotropic magnetic interactions and the ordering of the solute in the mesophase. -
Asymmetric Lewis Acid Catalysis Directed by Octahedral Rhodium Centrochirality† Cite This: Chem
Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Asymmetric Lewis acid catalysis directed by octahedral rhodium centrochirality† Cite this: Chem. Sci.,2015,6,1094 Chuanyong Wang,‡a Liang-An Chen,‡b Haohua Huo,a Xiaodong Shen,a Klaus Harms,a Lei Gongb and Eric Meggers*ab A rhodium-based asymmetric catalyst is introduced which derives its optical activity from octahedral centrochirality. Besides providing the exclusive source of chirality, the rhodium center serves as a Lewis acid by activating 2-acyl imidazoles through two point binding and enabling a very effective asymmetric induction mediated by the propeller-like C2-symmetrical ligand sphere. Applications to asymmetric Michael additions (electrophile activation) as well as asymmetric a-aminations (nucleophile activation) Received 9th October 2014 are disclosed, for which the rhodium catalyst is found to be overall superior to its iridium congener. Due Accepted 7th November 2014 to its straightforward proline-mediated synthesis, high catalytic activity (catalyst loadings down to 0.1 DOI: 10.1039/c4sc03101f mol%), and tolerance towards moisture and air, this novel class of chiral-at-rhodium catalysts will likely www.rsc.org/chemicalscience to become of widespread use as chiral Lewis acid catalysts for a large variety of asymmetric transformations. Creative Commons Attribution 3.0 Unported Licence. Lewis acids are capable of activating a large variety of carbon- now wish to report for the rst time that rhodium can also serve heteroatom and carbon–carbon bond forming reactions and as the combined source of centrochirality and Lewis acidity in chiral Lewis acids have therefore become indispensable tools substitutionally labile octahedral metal complexes. -
The Control of Stereochemistry by the Pentafluorosulfanyl Group
Organic & Biomolecular Chemistry View Article Online PAPER View Journal | View Issue The control of stereochemistry by the pentafluorosulfanyl group† Cite this: Org. Biomol. Chem., 2018, 16, 3151 Paul R. Savoie, Cortney N. von Hahmann, Alexander Penger, Zheng Wei and John T. Welch * The influence of pentafluorosulfanylation on biological activity has been revealed in numerous compara- tive studies of biologically active compounds, but considerably less is known about the influence of pen- tafluorosulfanylation on reactivity. Among the distinctive properties of the pentafluorosulfanyl group is the profound dipole moment that results from introduction of this substituent. It has been shown that dipolar Received 20th December 2017, effects coupled with the steric demand of the SF5 group may be employed to influence the stereo- Accepted 3rd April 2018 chemistry of reactions, especially those processes with significant charge separation in the transition DOI: 10.1039/c7ob03146g state. The Staudinger ketene-imine cycloaddition reaction is an ideal platform for investigation of dipolar rsc.li/obc control of diastereoselectivity by the pentafluorosulfanyl group. Introduction ation into a hydrocarbon chain, the restricted rotation about the carbon–sulfur bond that results from interactions with Numerous pentafluorosulfanyl(SF5)-containing organic nearby methylene groups, can lead to localized conformational – compounds1 10 have been prepared that have potential utility rigidity of the alkyl chain.21,22 in drug discovery, agrochemical synthesis and materials -
Page 1 of 108 RSC Advances
RSC Advances 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. This Accepted Manuscript will be replaced by the edited, formatted and paginated article as soon as this 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/advances Page 1 of 108 RSC Advances Applications of oxazolidinones as chiral auxiliaries in the asymmetric alkylation reaction applied to total synthesis Majid M. Heravi,* Vahideh Zadsirjan, Behnaz Farajpour Department of Chemistry, School of Science, Alzahra University, Vanak, Tehran, Iran Email: [email protected] Abstract Various chiral oxazolidinones (Evans' oxazolidinones) have been employed as effective chiral auxiliaries in the asymmetric alkylation of different enolates. This strategy has been found promising and successful when used as key step (steps) in the total synthesis of several biologically active natural products. In this report, we try to underscore the applications of Manuscript oxazolidinones as chiral auxiliary in asymmetric alkylation, and particularly in crucial chiral inducing steps in the total synthesis of natural products, showing biological activities. -
Chirality in Chemical Molecules
Chirality in Chemical Molecules. Molecules which are active in human physiology largely function as keys in locks. The active molecule is then called a ligand and the lock a receptor. The structures of both are highly specific to the degree that if one atom is positioned in a different position than that required by the receptor to be activated, then no stimulation of the receptor or only partial activation can take place. Again in a similar fashion if one tries to open the front door with a key that looks almost the same than the proper key for that lock, one will usually fail to get inside. A simple aspect like a lengthwise groove on the key which is on the left side instead of the right side, can mean that you can not open the lock if your key is the “chirally incorrect” one. The second aspect to understand is which molecules display chirality and which do not. The word chiral comes from the Greek which means “hand-like”. Our hands are mirror images of each other and as such are not identical. If they were, then we would not need a right hand and left hand glove. We can prove that they are not identical by trying to lay one hand on top of the other palms up. When we attempt to do this, we observe that the thumbs and fingers do not lie on top of one another. We say that they are non-super imposable upon one another. Since they are not the same and yet are mirror images of each other, they are said to exhibit chirality. -
Chapter 4: Stereochemistry Introduction to Stereochemistry
Chapter 4: Stereochemistry Introduction To Stereochemistry Consider two of the compounds we produced while finding all the isomers of C7H16: CH3 CH3 2-methylhexane 3-methylhexane Me Me Me C Me H Bu Bu Me Me 2-methylhexane H H mirror Me rotate Bu Me H 2-methylhexame is superimposable with its mirror image Introduction To Stereochemistry Consider two of the compounds we produced while finding all the isomers of C7H16: CH3 CH3 2-methylhexane 3-methylhexane H C Et Et Me Pr Pr 3-methylhexane Me Me H H mirror Et rotate H Me Pr 2-methylhexame is superimposable with its mirror image Introduction To Stereochemistry Consider two of the compounds we produced while finding all the isomers of C7H16: CH3 CH3 2-methylhexane 3-methylhexane .Compounds that are not superimposable with their mirror image are called chiral (in Greek, chiral means "handed") 3-methylhexane is a chiral molecule. .Compounds that are superimposable with their mirror image are called achiral. 2-methylhexane is an achiral molecule. .An atom (usually carbon) with 4 different substituents is called a stereogenic center or stereocenter. Enantiomers Et Et Pr Pr Me CH3 Me H H 3-methylhexane mirror enantiomers Et Et Pr Pr Me Me Me H H Me H H Two compounds that are non-superimposable mirror images (the two "hands") are called enantiomers. Introduction To Stereochemistry Structural (constitutional) Isomers - Compounds of the same molecular formula with different connectivity (structure, constitution) 2-methylpentane 3-methylpentane Conformational Isomers - Compounds of the same structure that differ in rotation around one or more single bonds Me Me H H H Me H H H H Me H Configurational Isomers or Stereoisomers - Compounds of the same structure that differ in one or more aspects of stereochemistry (how groups are oriented in space - enantiomers or diastereomers) We need a a way to describe the stereochemistry! Me H H Me 3-methylhexane 3-methylhexane The CIP System Revisited 1. -
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). -
1,2-Asymmetric Induction in Carbonyl Compounds - a Computational Study
1,2-Asymmetric Induction in Carbonyl Compounds - A Computational Study by Jeffrey Retallick B.Sc., University of New Brunswick, 2015 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science In the Graduate Academic Unit of Chemistry Supervisor(s): Ghislain Deslongchamps, Ph.D., Chemistry Examining Board: Rodney Cooper, M.Sc., Computer Science, Chair External Examiner: Ben Newling, Ph.D., Physics This thesis is accepted by the Dean of Graduate Studies THE UNIVERSITY OF NEW BRUNSWICK October, 2019 © Jeffrey Retallick, 2020 Abstract In asymmetric synthesis, it is important to reliably predict the major stereoisomeric prod- uct of a reaction. One such reaction is the nucleophilic addition to a carbonyl compound featuring an adjacent chiral carbon. Several reaction models exist in literature to predict the facial selectivity of these reactions. These models provide simple visual drawings to quickly predict the major product of such a reaction without requiring exhaustive quantum mechanical calculations. These models are used on a daily basis, and some models per- form better than others, making it valuable to investigate which ones are the most effective. For the first time in this thesis, high-level computations have been performed on all of the literature models to verify their efficacy. The results of this thesis offers a definitive answer that the Felkin-Anh and Wintner models are the most effective, and that bent bond theory offers an interesting insight on the mechanics of these reactions. ii Dedication Kyle, Nan, and Taryn. iii Acknowledgements Thanks to my family for their support. Ghislain, thank you for putting up with me over the past while. -
APPLICATIONS in ASYMMETRIC SYNTHESIS Carlos
324 SYNTHESIS OF OCTAHYDROBENZO - 1, 2,3 - DIAZAPHOSPHOLIDINE - 2 - OXIDES AND THEIR DERIVATIVES: APPLICATIONS IN ASYMMETRIC SYNTHESIS DOI: http://dx.medra.org/ 10.17374/targets.2020.23.324 Carlos Cruz - Hernández a , José M. Landeros a , Eusebio Juaristi * a,b a Departamento de Química, Centro de Investigación y de E studios Avanzados, Avenida IPN 2508, 07360 Ciudad de México, Mexico b El Colegio Nacional, Luis González Obregón 23, Centro Histórico, 06020 Ciudad de México, Mexico (e - mail: [email protected]; [email protected]) Abstract. This chapter outlines recent efforts devoted to the synthesis of heterocycles that include the octahydrobenzo - 1,3,2 - diazaphospholidine - 2 - oxide fragment, as well as their application in asymmetri c synthesis. The first part of this review provides a brief discussion of the general structural characteristics of this phosphorus - containing heterocyclic scaffold. The second part describes the synthetic paths that were undertaken to synthesize the desir ed heterocycles , as well as some relevant considerations pertaining the spectroscopic characterization of the phosphorus - containing heterocycles of interest . The third part provides several illustrative examples where the novel chiral heterocycles were employed in ena ntioselective synthesis. The new phosphorus - containing heterocycles proved useful : i) as chiral auxiliaries in nucleophilic addition reactions, as well as as imine activators in electrophilic addition reactions; ii ) as c hiral ligands i n nucleophilic allylation and crotonylation of prochiral aldehydes , and iii) as c hiral organocatalysts in enantioselective aldol, Michael, and cascade reactions. Contents 1. Introduction 2. Synthesis of the octahydrobenzo - 1,3,2 - diazaphospho lidine - 2 - oxide s 2.1 . Conformational and configurational assignments 3 .