DOCSLIB.ORG

Heck Reaction—State of the Art

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

catalysts Review Heck Reaction—State of the Art ID SangeetaReview Jagtap DepartmentHeck of Reaction—State Chemistry, Baburaoji Gholap College,of the Sangvi, Art Pune 411027, India; [email protected]; Tel.: +91-20-2728-0204 Sangeeta Jagtap Received: 20 August 2017; Accepted: 6 September 2017; Published: 11 September 2017 Department of Chemistry, Baburaoji Gholap College, Sangvi, Pune 411027, India; Abstract:[email protected];The Heck reaction is one Tel.: of+91 the‐20‐2728 most‐0204 studied coupling reactions and is recognized with the NobelReceived: Prize in 20 Chemistry.August 2017; Accepted: Thousands 6 September of articles, 2017; hundreds Published: 11 of September reviews and2017 a number of books have been published on this topic. All reviews are written exhaustively describing the various aspects of HeckAbstract: reaction The andHeck refer reaction to the is one work of donethe most hitherto. studied Looking coupling atreactions the quantum and is recognized of the monographs with published,the Nobel and Prize the in reviews Chemistry. based Thousands on them, of articles, we found hundreds a necessity of reviews to summarize and a number all of reviews books on have been published on this topic. All reviews are written exhaustively describing the various Heck reaction about catalysts, ligands, suggested mechanisms, conditions, methodologies and the aspects of Heck reaction and refer to the work done hitherto. Looking at the quantum of the compoundsmonographs formed published, via Heck and reaction the reviews in one based review on andthem, generate we found a resource a necessity of information.to summarize Oneall can find almostreviews allon the Heck catalysts reaction used soabout far forcatalysts, Heck reaction ligands, in suggested this review. mechanisms, conditions, methodologies and the compounds formed via Heck reaction in one review and generate a resource Keywords:of information.Heck reaction; One can reviews;find almost C-C all coupling;the catalysts catalysis; used so far mechanism; for Heck reaction application in this review. Keywords: Heck reaction; reviews; C‐C coupling; catalysis; mechanism; application 1. Introduction The1. Introduction new era of research started after the introduction of coupling reactions, i.e., carbon–carbon bond forming reactions like Heck [1], Suzuki [2], Sonogoshira [3], Negishi [4], Kumada [5], Stille [6], The new era of research started after the introduction of coupling reactions, i.e., carbon–carbon Tsuji-Trostbond forming [7], etc. reactions These reactions like Heck have [1], Suzuki played [2], an Sonogoshira enormously [3], decisive Negishi and [4], importantKumada [5], role Stille in [6], shaping chemicalTsuji‐ synthesisTrost [7], etc. and These have reactions revolutionized have played the way an oneenormously thinks aboutdecisive synthetic and important organic role chemistry. in The Heckshaping reaction chemical (Equation synthesis (1))and ishave used revolutionized extensively the in manyway one syntheses, thinks about including synthetic agrochemical, organic fine chemicals,chemistry. The pharmaceutical, Heck reaction etc.(Equation The reaction(1)) is used was extensively introduced in bymany Mizoroki syntheses, [8] including and Heck [9] independentlyagrochemical, more fine thanchemicals, four pharmaceutical, decades ago. etc. It has The drawn reaction much was introduced attention by due Mizoroki to high [8] efficiency and and simplicity.Heck [9] independently Heck methodology more than is four attractive decades from ago. a It synthetic has drawn point much of attention view because due to of high its high chemoselectivityefficiency and andsimplicity. mild reactionHeck methodology conditions is attractive along with from low a synthetic toxicity point and of cost view of because the reagent of if, specifically,its high thechemoselectivity catalyst is recycled. and mild reaction conditions along with low toxicity and cost of the reagent if, specifically, the catalyst is recycled. (1) (1) The Heck reaction is described as a vinylation or arylation of olefins where a large variety of The Heck reaction is described as a vinylation or arylation of olefins where a large variety of olefins can be used, like derivatives of acrylates, styrenes or intramolecular double bonds. The aryl olefinshalide can variants be used, developed like derivatives in addition of to acrylates, typical aryl styrenes bromides or and intramolecular iodides are aromatic double triflates, bonds. aroyl The aryl halidechlorides, variants aryl developed sulfonyl in chlorides, addition aromatic to typical diazonium aryl bromides salts, aroyl and iodidesanhydrides, are aromatic aryl chlorides triflates, and aroyl chlorides,arylsilanols. aryl sulfonyl The catalyst chlorides, is the essential aromatic part of diazonium a reaction where salts, a aroyl variety anhydrides, of metals along aryl with chlorides a huge and arylsilanols.range of Theligands catalyst is studied. is the Significant essential progress part of a for reaction the preparation where a and variety characterization of metals along of variety with of a huge rangeligands of ligands and catalysts is studied. has Significantbeen made for progress avoiding for protection the preparation and deprotection and characterization procedures, therefore of variety of ligandsallowing and catalysts for syntheses has beento be carried made forout avoiding in fewer steps. protection Development, and deprotection novel catalytic procedures, properties thereforeand allowingextensive for syntheses mechanistic to studies be carried are summarized out in fewer in steps. several Development, reviews based novel on seminal catalytic work properties of many and researchers and reviewers as described in following sections. Palladium is usually the preferred metal extensive mechanistic studies are summarized in several reviews based on seminal work of many as it tolerates a wide variety of functional groups and it has a remarkable ability to assemble C‐C researchers and reviewers as described in following sections. Palladium is usually the preferred metal bonds between appropriately functionalized substrates. Most palladium based methodologies as it toleratesproceed with a wide stereo variety‐ and of regioselectivity functional groups and andwith it excellent has a remarkable yields. Generally, ability to the assemble less crowded C-C bonds between appropriately functionalized substrates. Most palladium based methodologies proceed with Catalysts 2017, 7, 267; doi:10.3390/catal7090267 www.mdpi.com/journal/catalysts Catalysts 2017, 7, 267; doi:10.3390/catal7090267 www.mdpi.com/journal/catalysts Catalysts 2017, 7, 267 2 of 53 stereo- and regioselectivity and with excellent yields. Generally, the less crowded structure is preferred during Heck reaction, and often favours a trans product. Few mechanisms are also supported by the discussionCatalysts 2017 on, 7 the, 267 regioselectivity and stereoselectivity of Heck reaction. 2 of 53 Sometimes compounds such as TBAB (Tetra butyl ammonium bromide) are added in the reactionstructure mixture is preferred along with during organic Heck reaction, or inorganic and basesoften favours needed a for trans the product. sequestration Few mechanisms of acid generated. are Typicalalso supported solvents for by the discussion Heck reaction on the are regioselectivity dipolar aprotic and solvents stereoselectivity like DMF of Heck (dimethyl reaction. formamide) and NMPSometimes (N-methyl-2-pyrrolidone), compounds such as however, TBAB (Tetra the reaction butyl ammonium is also performed bromide) in manyare added other in different the reaction mixture along with organic or inorganic bases needed for the sequestration of acid solvents and in fact there are large numbers of reviews dedicated to the use of various solvents. generated. Typical solvents for the Heck reaction are dipolar aprotic solvents like DMF (dimethyl Besides these, many manuscripts describe the reaction in the absence of one of the component (other formamide) and NMP (N‐methyl‐2‐pyrrolidone), however, the reaction is also performed in many thanother substrates) different such solvents as ligand and in free,fact there organic are large solvent numbers free and of reviews so on. Recent dedicated publications to the use of also various describe howsolvents. to recover Besides used these, catalyst many specially manuscripts using aqueous describe medium the reaction which in implies the absence the potential of one forof greenerthe approachcomponent for organic (other than reactions. substrates) such as ligand free, organic solvent free and so on. Recent publicationsThere are aalso large describe number how of to excellent recover used reviews catalyst available specially on Heckusing reactionaqueous andmedium related which topics basedimplies on applications, the potential for mechanism, greener approach quest for for high organic turn reactions. over numbers (TONs), asymmetric synthesis, separationThere techniques, are a large etc. number In addition of excellent to this, reviews there are available a few manuscripts on Heck reaction that give and a generalrelated topics overview aboutbased Heck on reaction,applications, some mechanism, of them are quest detailed for high and turn some over are numbers not so descriptive. (TONs), asymmetric Many reviews synthesis, discuss variousseparation catalysis techniques, techniques etc. with In addition certain aspectsto this, wherethere are along a few with manuscripts the Heck reaction, that give other
Recommended publications
  • Proquest Dissertations

    Proquest Dissertations

    The synthesis of highly substituted indoles via isonitriles Item Type text; Dissertation-Reproduction (electronic) Authors Kennedy, Abigail Rose Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 26/09/2021 04:52:53 Link to Item http://hdl.handle.net/10150/290368 INFORMATION TO USERS This manuscript has l)een reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be firom any type of computer printer. The quality of this raproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author dkJ not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sectkms with small overiaps. Photographs included in the original manuscript have been reproduced xerographicaliy in this copy. Higher quality 6' x 9* black and white photographk: prints are available for any photographs or illustrations appearing in this copy for an additk)nai charge.
  • The Synthesis of Molecules Containing Quaternary Stereogenic Centers Via the Intramolecular Asymmetric Heck Reaction

    The Synthesis of Molecules Containing Quaternary Stereogenic Centers Via the Intramolecular Asymmetric Heck Reaction

    The Synthesis of Molecules Containing Quaternary Stereogenic Centers via the Intramolecular Asymmetric Heck Reaction Reported by Eric P. Gillis April 19, 2007 INTRODUCTION The enantioselective synthesis of compounds containing quaternary stereocenters continues to be a challenging endeavor and is a field of intense interest and development.1,,,,2 3 4 5 From the perspective of methods development, the asymmetric synthesis of compounds containing quaternary stereocenters poses a distinct challenge due to the sterically congested environment in which C-C bonds must be formed and stereochemical information must be transferred. Existing asymmetric methods have been applied successfully in desymmetrization processes that transform prochiral quaternary centers into stereodefined quaternary centers. However, for processes in which a quaternary stereocenter is created directly via a C-C bond forming reaction, only a few asymmetric reactions have been fruitful. The diversity in the array of methods that exist for the synthesis of compounds containing quaternary stereocenters is necessitated in part because of the number of distinct quaternary stereocenter architectures that are possible (Scheme 1). The construction of acyclic quaternary stereocenters is particularly challenging due to the number of degrees of freedom associated with these structures. However, promising results for the construction of these stereocenters via allylation,6 allylic alklyation,7 and Michael addition8 have been reported recently. For the synthesis of cyclic quaternary stereocenters a number of methods have been employed successfully including the intramolecular Heck reaction,9 alkylation,10 arylation,11 and Michael addition12. Fused bicyclic quaternary stereocenters are generally accessed via the desymmetrization of a prochiral quaternary center. In this regard, theoretically any SCHEME 1.
  • Advances in Metal-Catalyzed Cross-Coupling Reactions of Halogenated Quinazolinones and Their Quinazoline Derivatives

    Advances in Metal-Catalyzed Cross-Coupling Reactions of Halogenated Quinazolinones and Their Quinazoline Derivatives

    Molecules 2014, 19, 17435-17463; doi:10.3390/molecules191117435 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.com/journal/molecules Review Advances in Metal-Catalyzed Cross-Coupling Reactions of Halogenated Quinazolinones and Their Quinazoline Derivatives Malose Jack Mphahlele * and Marole Maria Maluleka Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, P.O. Box 392, Pretoria 0003, South Africa; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +27-12-429-8805; Fax: +27-12-429-8549. External Editor: Derek J. McPhee Received: 26 August 2014; in revised form: 10 October 2014 / Accepted: 21 October 2014 / Published: 29 October 2014 Abstract: Halogenated quinazolinones and quinazolines are versatile synthetic intermediates for the metal-catalyzed carbon–carbon bond formation reactions such as the Kumada, Stille, Negishi, Sonogashira, Suzuki-Miyaura and Heck cross-coupling reactions or carbon-heteroatom bond formation via the Buchwald-Hartwig cross-coupling to yield novel polysubstituted derivatives. This review presents an overview of the application of these methods on halogenated quinazolin-4-ones and their quinazolines to generate novel polysubstituted derivatives. Keywords: halogenoquinazolin-4-ones; halogenoquinazolines; cross-coupling reactions 1. Introduction and Scope In recent years, the development of strategies to efficiently functionalize presynthesized halogenated quinazolinones and quinazolines or their tosylate derivatives via metal-catalyzed cross-coupling reactions to afford novel polycarbo- or polyheteroatom-substituted derivatives with potential application in pharmaceuticals and materials has attracted considerable interest. The 3-substituted 2,6-diarylquinazolin-4(3H)-ones 1 and 2 (Figure 1), for example, were previously prepared via Suzuki-Miyaura cross-coupling of the corresponding 6-halogenated 4(3H)-oxo precursors and were found to be ghrelin receptor and vasopressin V1b receptor antagonists, respectively [1,2].
  • Stilbene Synthesis by Mizoroki–Heck Coupling Reaction Under Microwave Irradiation

    Stilbene Synthesis by Mizoroki–Heck Coupling Reaction Under Microwave Irradiation

    An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation Carolina S. García, Paula M. Uberman and Sandra E. Martín* Full Research Paper Open Access Address: Beilstein J. Org. Chem. 2017, 13, 1717–1727. INFIQC-CONICET- Universidad Nacional de Córdoba, Departamento doi:10.3762/bjoc.13.166 de Química Orgánica, Facultad de Ciencias Químicas, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA, Córdoba, Received: 25 April 2017 Argentina Accepted: 04 August 2017 Published: 18 August 2017 Email: Sandra E. Martín* - [email protected] Associate Editor: L. Vaccaro * Corresponding author © 2017 García et al.; licensee Beilstein-Institut. License and terms: see end of document. Keywords: aqueous reaction medium; MAOS; Mizoroki–Heck reaction; Pd nanoparticle; sustainable organic synthesis Abstract Aqueous Mizoroki–Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The reaction was carried out in a short reaction time and with low catalyst loading, leading to high turnover frequency (TOFs of the order of 100 h−1). The advantages like operational simplicity, high robust- ness, efficiency and turnover frequency, the utilization of aqueous media and simple product work-up make this protocol a great option for stilbene syntheses by Mizoroki–Heck reaction. Introduction Palladium-catalyzed reactions have emerged as an important basic types of Pd-catalyzed reactions, particularly the vinyl- tool for organic synthesis. Among them, cross-coupling and ation of aryl/vinyl halides or triflates [7-10], explored not only coupling reactions have been broadly applied for C–C and in the inter- and intramolecular version [2,11-13], but also in C–heteroatom bond formation [1-6].
  • Recyclable Catalysts for Alkyne Functionalization

    Recyclable Catalysts for Alkyne Functionalization

    molecules Review Recyclable Catalysts for Alkyne Functionalization Leslie Trigoura 1,2 , Yalan Xing 1,* and Bhanu P. S. Chauhan 2,* 1 Department of Chemistry, William Paterson University of New Jersey, 300 Pompton Road, Wayne, NJ 07470, USA; [email protected] 2 Engineered Nanomaterials Laboratory, Department of Chemistry, William Paterson University of New Jersey, 300 Pompton Road, Wayne, NJ 07470, USA * Correspondence: [email protected] (Y.X.); [email protected] (B.P.S.C.); Tel.: +1-973-720-2470 (B.P.S.C.) Abstract: In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have in- corporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane- encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic frame- work (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowl- edge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis. Keywords: green catalysts; nanosystems; nanoscale catalysts; catalyst modulation; alkyne functional- ization; coupling reactions Citation: Trigoura, L.; Xing, Y.; 1. Introduction Chauhan, B.P.S. Recyclable Catalysts for Alkyne Functionalization. Alkyne functionalization methods constitute one of the most relevant topics in organic Molecules 2021, 26, 3525. https:// synthesis and has resulted in numerous advancements over several years.
  • Advances in Cross-Coupling Reactions

    Advances in Cross-Coupling Reactions

    molecules Editorial Advances in Cross-Coupling Reactions José Pérez Sestelo * and Luis A. Sarandeses * Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain * Correspondence: [email protected] (J.P.S.); [email protected] (L.A.S.); Tel.: +34-881-012-041 (J.P.S.); +34-881-012-174 (L.A.S.) Received: 28 September 2020; Accepted: 30 September 2020; Published: 1 October 2020 Cross-coupling reactions stand among the most important reactions in chemistry [1,2]. Nowadays, they are a highly valuable synthetic tool used for the preparation of a wide variety of organic compounds, from natural and synthetic bioactive compounds to new organic materials, in all fields of chemistry [3]. Almost 50 years from its discovery, the research in this topic remains active, and important progresses are accomplished every year. For this reason, we believe that a Special Issue on this topic is of general interest for the chemistry community. Advances in cross-coupling reactions have been developed with the aim to expand the synthetic utility of the methodology, through the involvement of new components, reaction conditions, and therefore, novel synthetic applications [4]. Although initially the term “cross-coupling” referred to the reaction of an organometallic reagent with an unsaturated organic halide or pseudohalide under transition metal catalysis, currently the definition is much more general and applies to reactions involving other components, conditions, and more complex synthetic transformations. In addition to the well-known and recognized cross-coupling reactions using organoboron (Suzuki-Miyaura), organotin (Stille), organozinc (Negishi), or organosilicon (Hiyama) nucleophiles, reactions involving other organometallic reagents such as organoindium [5,6], organolithium [7], and Grignard reagents [8] are now useful synthetic alternatives.
  • Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions

    Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions

    catalysts Review Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions Younis Baqi Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box 36, Muscat 123, Oman; [email protected]; Tel.: +968-2414-1473 Abstract: Cross-coupling reactions furnishing carbon–carbon (C–C) and carbon–heteroatom (C–X) bond is one of the most challenging tasks in organic syntheses. The early developed reaction protocols by Ullmann, Ullman–Goldberg, Cadiot–Chodkiewicz, Castro–Stephens, and Corey–House, utilizing elemental copper or its salts as catalyst have, for decades, attracted and inspired scientists. However, these reactions were suffering from the range of functional groups tolerated as well as severely restricted by the harsh reaction conditions often required high temperatures (150–200 ◦C) for extended reaction time. Enormous efforts have been paid to develop and achieve more sustainable reaction conditions by applying the microwave irradiation. The use of controlled microwave heating dramatically reduces the time required and therefore resulting in increase in the yield as well as the efficiency of the reaction. This review is mainly focuses on the recent advances and applications of copper catalyzed cross-coupling generation of carbon–carbon and carbon–heteroatom bond under microwave technology. Keywords: cross-coupling reaction; Cu catalyst; microwave irradiation; methodology; synthesis 1. Introduction Carbon–carbon (C–C) and carbon–heteroatom (C–X) bond formations through cross- Citation: Baqi, Y. Recent Advances in coupling reactions represents as one of the most useful strategy in the synthetic organic Microwave-Assisted chemistry, hence many procedures and methodologies have been developed and published Copper-Catalyzed Cross-Coupling in the literature.
  • Mechanisms of the Mizoroki-Heck Reaction

    Mechanisms of the Mizoroki-Heck Reaction

    P1: OTA c01 JWBK261-Oestreich December 16, 2008 10:9 Printer: Yet to come 1 Mechanisms of the Mizoroki–Heck Reaction Anny Jutand Departement´ de Chimie, Ecole Normale Superieure,´ CNRS, 24 Rue Lhomond, Paris Cedex 5, France 1.1 Introduction The palladium-catalysed Mizoroki–Heck reaction is the most efficient route for the vinyla- tion of aryl/vinyl halides or triflates. This reaction, in which a C C bond is formed, proceeds in the presence of a base (Scheme 1.1) [1, 2]. Nonconjugated alkenes are formed in re- actions involving cyclic alkenes (Scheme 1.2) [1e, 2a,c,e,g] or in intramolecular reactions (Scheme 1.3) [2b,d–g] with creation of stereogenic centres. Asymmetric Mizoroki–Heck reactions may be performed in the presence of a chiral ligand [2]. The Mizoroki–Heck reaction has been intensively developed from a synthetic and mechanistic point of view, as expressed by the impressive number of reviews and book chapters [1, 2]. In the late 1960s, Heck reported that arylated alkenes were formed in the reaction of alkenes with a stoichiometric amount of [Ar–Pd Cl] or [Ar–Pd–OAc], generated in situ by reacting ArHgCl with PdCl2 or ArHgOAc with Pd(OAc)2 respectively [3]. A mechanism was proposed which involves a syn migratory insertion of the alkene into the Ar–Pd bond, followedbyasyn β-hydride elimination of a hydridopalladium [HPdX] (X = Cl, OAc) (Scheme 1.4a). In the case of cyclic alkenes, in which no syn β-hydride is available, a syn β-hydride elimination occurs, leading to a nonconjugated alkene (Scheme 1.4b).
  • Regiocontrol in the Heck-Reaction and Fast Fluorous Chemistry

    Regiocontrol in the Heck-Reaction and Fast Fluorous Chemistry

    Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy 244 _____________________________ _____________________________ Regiocontrol in the Heck-Reaction and Fast Fluorous Chemistry BY KRISTOFER OLOFSSON ACTA UNIVERSITATIS UPSALIENSIS UPPSALA 2001 Dissertation for the Degree of Doctor of Philosophy (Faculty of Pharmacy) in Organic Pharmaceutical Chemistry presented at Uppsala University in 2001. Abstract Olofsson, K. 2001. Regiocontrol in the Heck-Reaction and Fast Fluorous Chemistry. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy 244. 74 pp. Uppsala. ISBN 91–554–4883–6 The palladium-catalysed Heck-reaction has been utilised in organic synthesis, where the introduction of aryl groups at the internal, β-carbon of different allylic substrates has been performed with high regioselectivity. The β-stabilising effect of silicon enhances the regiocontrol in the internal arylation of allyltrimethylsilane, while a coordination between palladium and nitrogen induces very high regioselectivities in the arylation of N,N-dialkylallylamines and the Boc-protected allylamine, producing β-arylated arylethylamines, which are of interest for applications in medicinal chemistry. Phthalimido-protected allylamines are arylated with poor to moderate regioselectivity. Single-mode microwave heating can reduce the reaction times of Heck-, Stille- and radical mediated reactions drastically from approximately 20 hours to a few minutes with, in the majority of cases, retained, high
  • Diphosphine Complexes on Alpo4-Sepiolite Supports

    Diphosphine Complexes on Alpo4-Sepiolite Supports

    catalysts Article Hydrogenation of α,β-Unsaturated Carbonyl Compounds over Covalently Heterogenized Ru(II) Diphosphine Complexes on AlPO4-Sepiolite Supports Verónica Caballero 1, Rafael Estevez 1, Diego Luna 1,* , Felipa M. Bautista 1 , Antonio A. Romero 1 , Laura Aguado-Deblas 1 , Jesús Hidalgo-Carrillo 1 and Isabel Romero 2 1 Departamento de Química Orgánica, Campus de Rabanales, Universidad de Córdoba, Ed. Marie Curie, 14014 Córdoba, Spain; [email protected] (V.C.); [email protected] (R.E.); [email protected] (F.M.B.); [email protected] (A.A.R.); [email protected] (L.A.-D.); [email protected] (J.H.-C.) 2 Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, C/M. Aurèlia Campmany, 69, E-17003 Girona, Spain; [email protected] * Correspondence: [email protected]; Tel.: +34-957212065 Abstract: In this work, the covalent immobilization of two ruthenium(II) complexes, II II i.e., [Ru Cl (bpea){(S)(-)(BINAP)}](BF4), 1, and [Ru Cl(bpea)(DPPE)](BF4), 2, where BINAP = 2,2’- bis(diphenylphosphino)-1,1’-binaphthyl and DPPE = 1,2-bis(diphenylphosphino)ethane, have been obtained (AlPO4-Sepiolite@1 and AlPO4-Sepiolite@2) by using a N-tridentate ligand N,N-bis-(2- pyridylmethyl)ethylamine (bpea), linked to an amorphous AlPO4-Sepiolite (20/80) inorganic support. Citation: Caballero, V.; Estevez, R.; This AlPO4-sepiolite support is able to immobilize the double amount of ruthenium complex (1.65%) Luna, D.; Bautista, F.M.; Romero, than the amorphous AlPO4 (0.89%). Both heterogenized complexes have been assessed as catalysts A.A.; Aguado-Deblas, L.; in the liquid phase hydrogenation of several substrates with carbonyl and/or olefinic double bonds Hidalgo-Carrillo, J.; Romero, I.
  • 1 CHEM 344 Organometallic Chemistry Practice Problems

    1 CHEM 344 Organometallic Chemistry Practice Problems

    CHEM 344 Organometallic Chemistry Practice Problems (not for credit) Name (print): TA name (print): _____________ 1) Careful choice of solvent is essential for the successful generation and reaction of a Grignard reagent. a) Explain why anhydrous diethyl ether and tetrahydrofuran (THF) are common solvents for the generation of Grignard reagents. b) Show the major product(s) of the reaction of 4-methylphenylmagnesium bromide (prepared in anhydrous diethyl ether) with benzophenone (dissolved in either ethanol, acetone, or diethyl ether). Assume acidic workup in each case. 1 2) The reaction of PhMgBr with cyclohexanone (C6H10O) followed by addition of sulfuric acid produces 1-phenylcyclohexene (C12H14) as shown below. The crude reaction mixture was analyzed by GC-mass spectrometry. Use the GC-MS data on the next page to identify the components of the crude product mixture and assess its purity. Draw a plausible electron-pushing mechanism for the formation of the major and minor products starting from bromobenzene. 2 3 3) 3) Show the product and justify the chemoselectivity of each of the following oxidative addition reactions. Show the oxidation state of the metal in the product. The table of C-X bond dissociation enthalpies of halobenzenes may be useful. a) b) c) C–X Bond Dissociation Enthalpies ° Ph–X H C–X (kcal/mol) 127 97 84 67 113 4 4) Transmetallation follows oxidative addition in a typical Pd-catalyzed coupling cycle. The process of transmetallation can be described by the following equilibrium: The process is thermodynamically favorable for the production of M-R if XM > XM' (X = Pauling electronegativity, M/M' = metal, R = organic group, X= halide).
  • Efficient Stille Cross-Coupling Reaction Catalyzed by the Pd(Oac

    Efficient Stille Cross-Coupling Reaction Catalyzed by the Pd(Oac

    Efficient Stille Cross-Coupling Reaction found that Dabco was a highly efficient ligand for the - Catalyzed by the Pd(OAc)2/Dabco Catalytic palladium-catalyzed Suzuki Miyaura cross-coupling re- System action resulting in high TONs (up to 950 000 TONs for the reaction of PhI and p-chlorophenylboronic acid) (eq 7,8 Jin-Heng Li,* Yun Liang, De-Ping Wang, Wen-Jie Liu, 1). Thus, we expected to extend the use of this type of Ye-Xiang Xie, and Du-Lin Yin ligand to other palladium-catalyzed transformations. Here, we report a stable, inexpensive, and efficient Key Laboratory of Chemical Biology & Traditional Pd(OAc)2/Dabco catalytic system for the Stille reactions Chinese Medicine Research, College of Chemistry and of aryl halides with organotin compounds. Chemical Engineering, Hunan Normal University, Changsha 410081, China [email protected] Received October 31, 2004 To evaluate the efficiency of Pd(OAc)2/Dabco in the Stille cross-coupling reaction, coupling of 4-bromoanisole (1a) with phenyltributyltin (2a) was first tested, and the An efficient Pd(OAc)2/Dabco-catalyzed Stille cross-coupling reaction procedure has been developed. In the presence of (2) For recent representative papers on phosphine-palladium cata- Pd(OAc)2 and Dabco (triethylenediamine), various aryl lysts, see: (a) Litter, A. F.; Fu, G. C. Angew. Chem., Int. Ed. 1999, 38, halides including aryl iodides, aryl bromides, and activated 2411. (b) Grasa, G. A.; Nolan, S. P. Org. Lett. 2001, 3, 119. (c) Litter, aryl chlorides were coupled efficiently with organotin com- A. F.; Schwarz, L.; Fu, G. C. J.