DOCSLIB.ORG

Zirconocene-Catalysed Diastereoselective Carbometalation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Zirconocene-Catalysed Diastereoselective Carbometalation Chemical Science Zirconocene -Catalysed Diastereoselective Carbometalation of Cyclobutenes Journal: Chemical Science Manuscript ID SC-EDG-06-2016-002617.R1 Article Type: Edge Article Date Submitted by the Author: 27-Jul-2016 Complete List of Authors: Marek, Ilan; Technion - Israel Institute of Technology, Department of Chemistry Raha Roy, Sudipta; Technion Israel Institute of Technology Eijsberg, Hendrik; Technion Israel Institute of Technology, Chemistry Bruffaerts, Jeffrey; Technion, Chemistry Page 1 of 6 PleaseChemical do not adjust Science margins Journal Name ARTICLE Zirconocene Catalyzed Diastereoselective Carbometalation of Cyclobutenes Received 00th January 20xx, a a a a* Accepted 00th January 20xx Sudipta Raha Roy , Hendrik Eijsberg , Jeffrey Bruffaerts and Ilan Marek DOI: 10.1039/x0xx00000x The regio- and diastereoselective zirconocene-catalyzed carbomagnesiation of cyclobutenes is therein reported to afford configurationally stable cyclobutylmagnesium species that could subsequently react with a large variety of electrophiles to www.rsc.org/ give polysubstituted cyclobutane species as a single diastereoisomer. disubstituted double bond, several issues such as 1) regio- and Introduction stereoselectivity of the addition; 2) configurational stability of the resulting sp3 organometallic species; 3) diastereoselectivity In the repertoire of strategies using organometallic species of the reaction with electrophiles are of major concern.7 that could lead to the efficient formation of two carbon- Finally, the enantioselectivity of the addition of a carbon carbon bonds per chemical step, the carbometalation reaction nucleophile across an unactivated double bond still represents to an unsaturated C-C bond represents a powerful strategy. a very challenging problem despite that it would acquire a The carbometalation reaction, defined as “the addition of a significant utility as a method for the creation of asymmetric carbon-metal bond of an organometallic across a carbon- vicinal carbon centers (Scheme 1, path c).8 Due to the inherent carbon unsaturated system leading to a new organometallic difficulties to achieve efficient carbometalation reaction across species that can be further functionalized” − is one of the most unactivated alkenes, most of the studies have focused on powerful approach that has been extensively used to perform 1 strained double bonds. As such, the copper-mediated the 1,2-bis-alkylation of alkynes. In this context, 9 2 carbometalation reaction of cyclopropenyl derivatives has organocopper as well as zirconocene-catalyzed 3 been investigated in details to provide a new route to enantio- methylalumination occupy a significant place due to their high and diastereoenriched configurationally stable cyclopropyl stereoselectivity, typically controlled by the nature of the metal species (Scheme 1, path d).10 However, all attempts to substituents on the triple bond (Scheme 1, path a for an extend the concept of carbometalation to less strained example of carbocupration). Besides forming stereodefined compounds such as cyclobutenes failed, most probably due to polysubstituted double bonds, the carbometalation reaction of the lower energy release during the addition step.11 None of alkynes has recently been considered as a new stereodefined the copper-catalyzed carbomagnesiation, copper-catalyzed chemical handle to prepare reactive intermediates for carbozincation, carbocupration with organocopper or subsequent creation of more complex molecular structures 3 organocuprate reactions in Et O or THF, could lead to the possessing sp -configurated stereocenters including 2 4 desired addition of the organometallic species across a double quaternary carbon stereocenter (Scheme 1, path b). 1,2- 12 3 bond embedded in a 4-membered ring (Scheme 1, path e). Disubstituted alkyl chains possessing sp stereocenters could Only Tortosa and coworkers recently reported the highly theoretically also be obtained through the carbometalation of 5 enantioselective desymmetrization of meso-cyclobutene appropriate alkenes (Scheme 1, path c). However, these through the copper-catalyzed borylation reaction.13 transformations are much more challenging than the As stereodefined cyclobutyl metal species en route to carbometalation reactions of alkynes since the carbometalated polysubstituted cyclobutane derivatives still represent an product is usually of similar reactivity than the starting important building block in the field of small ring chemistry,14 organometallic species and oligomerization reaction typically 6 we therefore decided to pursuit our efforts to functionalize occurs. Moreover, when the reaction is performed on - cyclobutene species into polysubstituted metalated cyclobutanes through carbometalation reaction, and more particularly through the Dzhemilev reaction. It should be a. The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and Lise Meitner-Minerva Center for Computational Quantum Chemistry, emphasized that all starting cyclobutenes 1 were prepared by Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel. E-mail: a rhodium-catalyzed intermolecular [2+2] cycloaddition of [email protected]; Fax: +972-4-829-37-09; Tel: +972-4-829-37-09. 15 † Footnotes relating to the title and/or authors should appear here. terminal alkynes with electron-deficient alkenes. Electronic Supplementary Information (ESI) available: Experimental procedures, spectroscopic data and copies of 1H and 13C NMR spectra. See DOI: 10.1039/x0xx00000x This journal is © The Royal Society of Chemistry 20xx J. Name., 2013, 00, 1-3 | 1 Please do not adjust margins PleaseChemical do not adjust Science margins Page 2 of 6 ARTICLE Journal Name Scheme 1. Carbometalation reactions Bn Bn O O O 1 1 1 R R2 O path a path b 1) R2[Cu] R N R N R3 N 2) ZnBr , R3CHO, O O 2 R2 [Cu] R2 CH Et Zn, CH I 2 2 2 2 Zn 4 CH 2 4 R 3SiO 2 Bn 1) R [Cu] R 3SiCl CH2I 50-70 % R1 H 3 2) R -X 87:13 to 98:2 dr R1 X X= oxazolidinone R2 R3 X = H OH O Bn 1) R2[Cu] 2) t-BuOOH R3 N 3) R3CH=O R1 R2 O O 45-62 % 90:1:4:5 to 94:1:2:3 dr path c Regioselectivity Stereoselectivity Configurational stability of C-[M] 1 1 R1 R R2 R R2 4 3 R -X R [M] + H H H H 2 3 R R [M] R3 R4 Diastereoselectivity Enantioselectivity path d 1 2 1 2 1) R3 Zn (1.2 eq.) R R R R 2 up to 97% CuX (0.5 mol%)/L (0.55 mol%) dr up >98:2:0:0 4 er up to 99:1 2) R -X 4 R3 R path e R2 R2 R3[Cu] R1 1 THF or Et O R 1 2 R3 the cyclobutyl magnesium V or cyclobutyl zirconocene species Results and discussion VI after transmetalation. The selectivity of the transmetalation is critical as the carbon attached to the zirconocene will then In this context, and as eluded previously we were particularly be subsequently reduced to regenerate the catalytic interested in the possibility to reach our goal through the zirconacyclopropane species I (see for example the diastereoselective zirconocene-catalyzed carbomagnesiation 16 preparation of VIII via the reduction depicted in VII). If one reaction (Dzhemilev reaction) as described in Scheme 2. assumes that the reaction would only provide V, then the In this transformation, the addition of ethylmagnesium 5 cyclobutyl magnesium derivative VIII may be expected bromide to a catalytic amount of dichlorobis( - whereas if the transmetalation occurs to provide VI, the cyclopentadienyl)zirconium(IV) [Cp2ZrCl2] should provide the cyclobutyl ethylmagnesium species IX is anticipated. Finally, if zirconacyclopropane I that would in-situ react with the double one still assumes that the catalytic cycle would only provide bond of the cyclobutene 1 to form either the addition product VIII, the configurational stability of this cyclobutyl magnesium II or III. Each of these two possible regioisomers could be species as well as its reactivity towards electrophiles needs to present as potentially two diastereoisomers (II anti versus II be investigated in details. syn and III anti versus III syn). So, not only the regioselectivity Therefore, the Dzhemilev ethylmagnesiation of cyclobutene of the zirconocene-catalyzed carbomagnesiation of substituted catalyzed by dichlorobis((5-cyclopentadienyl)zirconium(IV) cyclobutene 1 should be controlled (II versus III) but also the proceeds by a rather convoluted process with potentially diastereoselectivity of the reaction (syn versus anti). Assuming several cyclic intermediates and the unique formation of VIII that from the four possible regio- and diastereoisomers only required a complete control of all the elementary steps. We the isomer II anti will be produced, the reaction of initially focused our attention to the diastereoselective ethylmagnesium bromide with the zirconacyclopentane IIanti zirconocene-mediated carbomagnesiation of cyclobutene 1a would then provide the ate-complex IV that may either lead to 2 | J. Name., 2012, 00, 1-3 This journal is © The Royal Society of Chemistry 20xx Please do not adjust margins Page 3 of 6 PleaseChemical do not adjust Science margins Journal Name ARTICLE Scheme 2. Proposed zirconocene-catalyzed diastereoselective ethylmagnesiation reaction of cyclobutene. 1 2 (R = (CH2)2Ph, R = Me) in THF and we were pleased to and the major isomer 2a was still observed with, however, observe that the addition reaction proceeds selectively under higher quantity of product resulting from the formation of the mild conditions (25 °C, 12 h) to provide 2a in 82% isolated yield opposite regioisomer III (II anti : III syn = 87:13, not shown In with >98:2 diastereoselectivity (Scheme 3). The relative Scheme
Load more

Recommended publications
  • This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G
    This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: • This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. • A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. • This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. • The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. • When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Development of Novel Metal-Catalysed Methods for the Transformation of Ynamides Thesis Submitted in Accordance with the Requirements of The University of Edinburgh for the Degree of Doctor of Philosophy By Donna L. Smith Supervised by Dr. Hon Wai Lam School of Chemistry College of Science and Engineering 2013 Declaration I hereby declare that, except where specific reference is made to other sources, the work contained within this thesis is the original work of my own research since the registration of the PhD degree in September 2009, and any collaboration is clearly indicated. This thesis has been composed by myself and has not been submitted, in whole or part, for any other degree, diploma or other qualification. Donna L. Smith 2 Abstract I. Rhodium-Catalysed Carbometalation of Ynamides using Organoboron Reagents As an expansion of existing procedures for the carbometalation of ynamides, it was discovered that [Rh(cod)(MeCN)2]BF4 successfully promotes the carbometalation of ynamides with organoboron reagents.
    [Show full text]
  • EI-ICHI NEGISHI Herbert C
    MAGICAL POWER OF TRANSITION METALS: PAST, PRESENT, AND FUTURE Nobel Lecture, December 8, 2010 by EI-ICHI NEGISHI Herbert C. Brown Laboratories of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, U.S.A. Not long ago, the primary goal of the synthesis of complex natural products and related compounds of biological and medicinal interest was to be able to synthesize them, preferably before anyone else. While this still remains a very important goal, a number of today’s top-notch synthetic chemists must feel and even think that, given ample resources and time, they are capable of synthesizing virtually all natural products and many analogues thereof. Accepting this notion, what would then be the major goals of organic synthesis in the twenty-first century? One thing appears to be unmistakably certain. Namely, we will always need, perhaps increasingly so with time, the uniquely creative field of synthetic organic and organometallic chemistry to prepare both new and existing organic compounds for the benefit and well-being of mankind. It then seems reasonably clear that, in addition to the question of what compounds to synthesize, that of how best to synthesize them will become increasingly important. As some may have said, the primary goal would then shift from aiming to be the first to synthesize a given compound to seeking its ultimately satisfactory or “last synthesis”. If one carefully goes over various aspects of organic synthetic methodology, one would soon note how primitive and limited it had been until rather recently, or perhaps even today. For the sake of argument, we may propose here that the ultimate goal of organic synthesis is “to be able to synthesize any desired and fundamentally synthesizable organic compounds (a) in high yields, (b) efficiently (in as few steps as possible, for example), (c) selectively, preferably all in t98–99% selectivity, (d) economically, and (e) safely, abbreviated hereafter as the y(es)2 manner.” with or without catalyst R1M + R2X R1R2 + MX R1, R2: carbon groups.
    [Show full text]
  • Transition Metals for Organic Synthesis
    Matthias Beller, Carsten Bolm Transition Metals for Organic Synthesis Building Blocks and Fine Chemicals © WILEY-VCH Weinheim • New York • Chichester • Brisbane • Singapore • Toronto Contents Volume 1 1 General 1 1.1 Basic Aspects of Organic Synthesis with Transition Metals (Barry M. Trost) 3 1.1.1 Chemoselectivity 4 1.1.2 Regioselectivity 6 1.1.3 Diastereoselectivity 7 1.1.4 Enantioselectivity 9 1.1.5 Atom Economy 10 1.1.6 Conclusion 11 References 12 1.2 Concepts for the Use of Transition Metals in Industrial Fine Chemical Synthesis (Wilhelm Keim) 14 1.2.1 General Principles 14 1.2.2 Use of Transition Metals in Fine Chemical Synthesis .... 15 1.2.3 Why are Transition Metals used in Fine Chemical Synthesis? 21 1.2.4 Considerations for the Future 22 References 22 2 Transition Metal-catalyzed Reactions 23 2.1 New Opportunities in Hydroformylation: Selected Syntheses of Intermediates and Fine Chemicals (Carlo Botteghi, Mauro Marchetti, Stefano Paganelli) ... 25 2.1.1 Introduction 25 2.1.2 Building Blocks for Pharmaceutical and Natural Products . 26 2.1.3 Building Blocks for Agrochemicals 40 2.1.4 Concluding Remarks 43 References 45 viii Contents 2.2 Hydrocarboxylation and Hydroesterification Reactions Catalyzed by Transition Metal Complexes (Bassam El Ali, Howard Alper) 49 2.2.1 Introduction 49 2.2.2 Intermolecular Hydrocarboxylation and Hydroesterification of Unsaturated Substrates 49 2.2.2.1 Hydrocarboxylation of Alkenes 49 2.2.2.2 Hydroesterification of Alkenes 53 2.2.2.3 Hydrocarboxylation and Hydroesterification of Allenes and Dienes
    [Show full text]
  • Catalytic Systems Based on Cp2zrx2 (X = Cl, H), Organoaluminum
    catalysts Article Catalytic Systems Based on Cp2ZrX2 (X = Cl, H), Organoaluminum Compounds and Perfluorophenylboranes: Role of Zr,Zr- and Zr,Al-Hydride Intermediates in Alkene Dimerization and Oligomerization Lyudmila V. Parfenova 1,* , Pavel V. Kovyazin 1, Almira Kh. Bikmeeva 1 and Eldar R. Palatov 2 1 Institute of Petrochemistry and Catalysis of Russian Academy of Sciences, Prospekt Oktyabrya, 141, 450075 Ufa, Russia; [email protected] (P.V.K.); [email protected] (A.K.B.) 2 Bashkir State University, st. Zaki Validi, 32, 450076 Ufa, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-347-284-3527 i i Abstract: The activity and chemoselectivity of the Cp2ZrCl2-XAlBu 2 (X = H, Bu ) and [Cp2ZrH2]2- ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head- to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp ZrH ·Cp ZrHCl·ClAlR ]·yRnAl(C F ) − were found to be the key intermediates of alkene 2 2 2 2 6 5 3 n dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers. Citation: Parfenova, L.V.; Kovyazin, P.V.; Bikmeeva, A.K.; Palatov, E.R.
    [Show full text]
  • Transmetalation
    Organic Chemistry IV Organometallic Chemistry for Organic Synthesis Prof. Paul Knochel LMU 2015 1 OCIV Prüfung: Freitag 17. Juli 2015 9-11 Uhr Wieland HS Wiederholungsklausur: Donnerstag 17. September 2015 12-14 Uhr Baeyer HS 2 Recommended Literature 1. F. A. Carey, R. J. Sundberg, Advanced Organic Chemistry, Fifth Edition Part A and Part B, Springer, 2008, ISBN-13: 978-0-387-68346-1 2. R. Brückner, Organic Mechanisms, Springer, 2010, ISBN: 978-3-642- 03650-7 3. L. Kürti, B. Czako, Strategic applications of named reactions in organic synthesis, Elsevier, 2005, ISBN-13: 978-0-12-429785-2 4. N. Krause, Metallorganische Chemie, Spektrum der Wissenschaft, 1996, ISBN: 3-86025-146-5 5. R. H. Crabtree, The organometallic chemistry of transition metals, Wiley- Interscience, 2005, ISBN: 0-471-66256-9 6. M. Schlosser, Organometallics in Synthesis – A manual, 2nd edition, Wiley, 2002, ISBN: 0-471-98416-7 7. K. C. Nicolaou, T. Montagnon, Molecules that changed the world, Wiley- VCH, 2008, ISBN: 978-527-30983-2 8. J. Hartwig, Organotransition Metal Chemistry: From Bonding to Catalysis, Palgrave Macmillan, 2009, ISBN-13: 978-1891389535 9. P. Knochel, Handbook of Functionalized Organometallics, Volume 1 und 2, Wiley-VCH, 2005, ISBN-13: 978-3-527-31131-6 3 Importance of organometallics 4 Industrial production Industrial annual production of various organometallics Organometallic production [T / year] Si 700 000 Pb 600 000 Al 50 000 Sn 35 000 Li 900 5 Organometallic reagents and catalysts for the organic synthesis 6 Historic point of view 1757 - Louis Cadet de Gassicourt (parisian apothecary) E. Frankland (1848), University of Marburg, initial goal: synthesis of an ethyl radical Universität Marburg (1848) 7 Organometallic chemistry of the XIX century 8 Organometallic chemistry of the XIX century 9 Reactivity of the Grignard reagents 10 Historic point of view Victor Grignard (1900) Karl Ziegler (1919) 11 Historic point of view first transition metal organometallics: Hein (1919) 12 Historic point of view 1951 : synthesis of ferrocene Pauson (Scotland) 7.
    [Show full text]
  • Part I. Inversion of Secondary Cyclic Grignard Reagents
    This dissertation has been , 69-11,692 microfilmed exactly as received PECHHOLD, Engelbert, 1933- STUDIES OF THE BEHAVIOR AND GENERATION OF GARB ANIONS: PART I. INVERSION OF SECONDARY CYCLIC GRIGNARD REAGENTS. PART II. FRAGMENTATION OF AZOFORMATE SALTS AND ACYLAZO COMPOUNDS WITH BASES. The Ohio State University, Ph.D., 1968 Chemistry, organic University Microfilms, Inc., Ann Arbor, Michigan ©Copyright "by- Engelbert Pechhold 1969 STUDIES OF THE BEHAVIOR MD GENERATION OF CARBANIONS PART I. INVERSION OF SECONDARY CYCLIC GRIGNARD REAGENTS PART II. FRAGMENTATION OF AZOFORMATE SADIS AND ACYLAZO COMPOUNDS WITH BASES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Engelbert Pechhold * # # * * # The Ohio State University 1968 Approved by •pV-gpa.-t— Adviser Department of Chemistry DEDICATION To my wife, Ingrid, and my parents, whose love, understanding, and encouragement have made this venture possible. ii ACKNOWLEDaEMElWS I -wish to express my deepest appreciation to Professor Gideon Fraenkel for suggestinf^ this problem, and for his guidance and encouragement throughout the course of this research. His assistance in the preparation of this dissertation is gratefully acknowledged. It is an understatement to say that without his un­ usual courage of conviction and high standards for academic perfor­ mance, this work could not have come into being. I owe special debt of gratitude to my colleagues for many suimtü-ating discussions of chemical matters and otherwise. In particular, I wish to express my gratitute to Dr. Don Dix, Dr. Dave Mams, and James Morton, who gave me much insight in ny research.
    [Show full text]
  • Theoretical Insight Into the Transmetalation of MOF-5 Lattices
    Article pubs.acs.org/cm When the Solvent Locks the Cage: Theoretical Insight into the Transmetalation of MOF‑5 Lattices and Its Kinetic Limitations ,† ‡ †,§ ‡ † Luca Bellarosa,* Carl K. Brozek, Max García-Melchor, Mircea Dinca,̆and Nuriá Lopeź † Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007 Tarragona, Spain ‡ Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States § SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States *S Supporting Information ABSTRACT: Transmetalation is an innovative postsynthetic strategy for tailoring the properties of metal−organic frameworks (MOFs), allowing stable unprecedented metal coordination environments. Although the experimental synthetic protocol is well- established, the underlying mechanism for transmetalation is still unknown. In this work, we propose two different solvent-mediated reaction paths for the Ni transmetalation in Zn- MOF-5 lattices through density functional theory simulations. In both mechanisms, the bond strength between the exchanged metal and the solvent is the key descriptor that controls the degree of transmetalation. We also show that the role of the solvent in this process is twofold: it initially promotes Zn exchange, but if the metal−solvent bond is too strong, it blocks the second transmetalation cycle by restricting the lattice flexibility. The competition between these two effects leads the degree of incorporation of metal into MOF-5 to display a volcano-type dependence with respect to the metal−solvent bond strength for different transition metal ions. ■ INTRODUCTION PSIM.26 Nevertheless, the dependence on the ligand field was The easiness with which metal−organic frameworks (MOFs)1 found to be opposite for Ni inserting into MOF-5 and Co into MFU-4l.
    [Show full text]
  • Download This Article PDF Format
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Nickel-catalyzed cyclization of alkyne-nitriles with organoboronic acids involving anti- Cite this: Chem. Sci.,2016,7,5815 carbometalation of alkynes† Xingjie Zhang, Xin Xie and Yuanhong Liu* A nickel-catalyzed regioselective addition/cyclization of o-(cyano)phenyl propargyl ethers with arylboronic acids has been developed, which provides an efficient protocol for the synthesis of highly functionalized Received 16th March 2016 1-naphthylamines with wide structural diversity. The reaction is characterized by a regioselective and Accepted 19th May 2016 anti-addition of the arylboronic acids to the alkyne and subsequent facile nucleophilic addition of the DOI: 10.1039/c6sc01191h resulting alkenylmetal to the tethered cyano group. Mechanistic studies reveal that a Ni(I) species might www.rsc.org/chemicalscience be involved in the catalytic process. to an exo-alkene upon cyclization3,4 (Scheme 1, eqn (1)). Creative Commons Attribution 3.0 Unported Licence. Introduction Cyclizations involving the regioselective formation of the Transition-metal-catalyzed cascade reactions consisting of alkenylmetal with a metal a-to the R1 substituent such as syn-B 5 multiple carbometalation steps have attracted considerable are quite rare (Scheme 1, eqn (2)), possibly because the attention in organic synthesis since these processes enable the subsequent cyclization process will involve a highly strained rapid assembly of complex structures in an efficient, atom- transition state. Thus,
    [Show full text]
  • Discovery of ZACA Reaction: Zr-Catalyzed Asymmetric
    Issue in Honor of Prof. Usein M. Dzhemilev ARKIVOC 2011 (viii) 34-53 Discovery of ZACA reaction : Zr-catalyzed asymmetric carboalumination of alkenes Ei-ichi Negishi Herbert C. Brown Laboratories of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, USA E-mail: [email protected] This paper is dedicated to Professor U. M. Dzhemilev in recognition and appreciation of his pioneering contributions to organometallic chemistry Abstract A single-stage, i.e., degree of polymerization of one, and enantioselective version of the Ziegler- Natta alkene polymerization was envisioned as a potentially significant and useful method for catalytic asymmetric C–C bond formation, shortly after the corresponding alkyne version involving Zr-catalyzed alkylalumination of alkynes was discovered in 1978. However, the discovery of such an asymmetric reaction proved to be a major challenge. At least three widely observable unwanted side reactions, i.e., (1) cyclic carbometalation, (2) β-H transfer hydrometalation, and (3) alkene polymerization, represented by the Ziegler-Natta polymerization, were noted and were to be avoided. With Zr as the metal at the catalytic center, we eventually came up with a notion that di- or multiple alkylation of Zr was to be avoided for achieving superior acyclic asymmetric carbometalation. This, in turn, led us to avoid the use of highly nucleophilic alkylmetals containing alkali metals and Mg. Aluminum used in Ziegler- Natta polymerization that can selectively monoalkylate Zr proved to be one of a very limited number of favorable metals. Even so, undesirable cyclic carbozirconation can occur in nonpolar solvents via intricate bimetallic routes to cyclic organozirconium species.
    [Show full text]
  • Oxidation of Organocopper Compounds
    Oxidation of Organocopper Compounds Sarah J. Aves and Dr. David R. Spring Department of Chemistry University of Cambridge Lensfield Road Cambridge CB2 1EW United Kingdom Tel.: +44 (0) 1223 336498 Fax: +44 (0) 1223 336362 E-mail: [email protected] [email protected] Oxidation of Organocopper Compounds Contents I. Introduction.................................................................................................................3 II. Formation of C-C Bonds............................................................................................. 4 A. Initial Studies.......................................................................................................... 4 B. Cross-coupling ........................................................................................................ 5 C. Biaryl Formation................................................................................................... 11 D. Intramolecular Bond Formation............................................................................ 14 E. Dimerisations of Heteroaromatics, Alkenyl and Alkyl Groups and Macrocycle Formation...................................................................................................................... 18 III. Formation of C-N Bonds ...................................................................................... 21 A. Initial Studies........................................................................................................ 21 B. Further Developments..........................................................................................
    [Show full text]
  • Carbometallation Chemistry
    Carbometallation chemistry Edited by Ilan Marek Generated on 01 October 2021, 10:03 Imprint Beilstein Journal of Organic Chemistry www.bjoc.org ISSN 1860-5397 Email: [email protected] The Beilstein Journal of Organic Chemistry is published by the Beilstein-Institut zur Förderung der Chemischen Wissenschaften. This thematic issue, published in the Beilstein Beilstein-Institut zur Förderung der Journal of Organic Chemistry, is copyright the Chemischen Wissenschaften Beilstein-Institut zur Förderung der Chemischen Trakehner Straße 7–9 Wissenschaften. The copyright of the individual 60487 Frankfurt am Main articles in this document is the property of their Germany respective authors, subject to a Creative www.beilstein-institut.de Commons Attribution (CC-BY) license. Carbometallation chemistry Ilan Marek Editorial Open Access Address: Beilstein J. Org. Chem. 2013, 9, 234–235. Schulich Faculty of Chemistry, Technion-Israel Institute of doi:10.3762/bjoc.9.27 Technology, Haifa 32000, Israel Received: 24 January 2013 Email: Accepted: 29 January 2013 Ilan Marek - [email protected] Published: 04 February 2013 This article is part of the Thematic Series "Carbometallation chemistry". Keywords: carbometallation Guest Editor: I. Marek © 2013 Marek; licensee Beilstein-Institut. License and terms: see end of document. Following the pioneering Ziegler addition of nucleophiles to in the 1,2-bisalkylation of nonactivated alkenes! In this nonactivated unsaturated carbon–carbon bonds, the controlled Thematic Series, you will find
    [Show full text]
  • In Situ Generation of Ru-Based Metathesis Catalyst. a Systematic 2 Study 3 4 Daniel S
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE Page 1 of 9 ACS Catalysis provided by Archive Ouverte en Sciences de l'Information et de la Communication 1 In Situ Generation of Ru-Based Metathesis Catalyst. A Systematic 2 Study 3 4 Daniel S. Müller,a Yann Raoul,b Jérôme Le Nôtre,c Olivier Basléa,† and Marc Mauduit a* 5 a 6 Univ Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR UMR 6226, F-35000 Rennes, France 7 b OLEON SAS, Venette BP 20609, 60206 Compiègne Cedex, France 8 c PIVERT SAS, Rue les Rives de l’Oise CS50149, 60201 Compiègne Cedex, France 9 10 KEYWORDS: Olefin metathesis, Ruthenium, Arene complexes, in situ, NHC ligand 11 12 ABSTRACT: A practical and cost-effective protocol for the in situ generation of Ru-based metathesis catalysts was developed. 13 Assembly of commercially available and inexpensive reagents [Ru(p-cymene)Cl2]2, SIPr.HCl and n-BuLi led to the formation of 18 14 electron arene-ruthenium complexes that, in the presence of additives such as alkynes, cyclopropenes and diazoesters, generated 15 highly selective and efficient catalytic systems applicable to a variety of olefin metathesis transformations. Notably, we were able 16 to achieve a productive TON of 4500 for the self-metathesis of methyl oleate, a reaction which could be easily upscaled to 2 kg. 17 18 19 20 Since its discovery in the mid 1950's, the metathesis reaction containing the saturated NHC ancillary ligand (SIMes) is quite gained significant importance for organic syntheses and unstable and remains difficult to isolate.10,18 Inspired by the 21 polymer chemistry.1 In its early days, the metathesis reaction pioneering work of Grubbs,14a Noels14c,16 and Dixneuf14b we 22 relied on ill-defined in situ generated catalysts.
    [Show full text]