DOCSLIB.ORG

Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments Reactions: Recent Developments Diego A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments Reactions: Recent Developments Diego A catalysts Review ReviewSolid-Supported Palladium Catalysts in Sonogashira Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments Reactions: Recent Developments Diego A. Alonso, Alejandro Baeza, Rafael Chinchilla *, Cecilia Gómez, Gabriela Guillena, IsidroDiego M. A. AlonsoPastor *ID and, Alejandro Diego J. BaezaRamónID , Rafael Chinchilla * ID , Cecilia Gómez, Gabriela Guillena, Isidro M. Pastor * ID and Diego J. Ramón ID Department of Organic Chemistry and Institute of Organic Synthesis (ISO), Faculty of Sciences, University of Alicante,Department PO ofBox Organic 99, 03080 Chemistry Alicante, and Spain Institute; [email protected] of Organic Synthesis (D.A.A.); (ISO), [email protected] Faculty of Sciences, (A.B.); University of Alicante,[email protected] PO Box (C.G.); 99, 03080 [email protected] Alicante, Spain; [email protected] (G.G.); [email protected] (D.A.A.); (D.J.R.) [email protected] (A.B.); *[email protected] Correspondence: (C.G.); [email protected] [email protected] (R.C.); [email protected] (G.G.); [email protected] (I.M.P); Tel.: (D.J.R.) +34-965-903-822 (R.C.) * Correspondence: [email protected] (R.C.); [email protected] (I.M.P); Tel.: +34-965-903-822 (R.C.) Received: 19 April 2018; Accepted: 9 May 2018; Published: 11 May 2018 Abstract:Received: 19The April Sonogashira 2018; Accepted: cross 9 May-coupling 2018; Published: reaction 11is Maythe 2018most frequently employed synthetic procedure for the preparation of arylated alkynes, which are important conjugated compounds with Abstract: The Sonogashira cross-coupling reaction is the most frequently employed synthetic multiple applications. Despite of their rather high price, this reaction is usually catalyzed by procedure for the preparation of arylated alkynes, which are important conjugated compounds palladium species, making the recovery and reuse of the catalyst an interesting topic, mainly for with multiple applications. Despite of their rather high price, this reaction is usually catalyzed by industrial purposes. Easy recycle can be achieved anchoring the palladium catalyst to a separable palladium species, making the recovery and reuse of the catalyst an interesting topic, mainly for support. This review shows recent developments in the use of palladium species anchored to industrial purposes. Easy recycle can be achieved anchoring the palladium catalyst to a separable different solid supports as recoverable catalysts for Sonogashira cross-coupling reactions. support. This review shows recent developments in the use of palladium species anchored to different solid supports as recoverable catalysts for Sonogashira cross-coupling reactions. Keywords: palladium; catalysis; Sonogashira reaction; supported reagents; cross-coupling reactions Keywords: palladium; catalysis; Sonogashira reaction; supported reagents; cross-coupling reactions 1. Introduction 1. IntroductionThe palladium-catalyzed Csp2-Csp coupling reaction between aryl or alkenyl halides or triflates and terminalThe palladium-catalyzed alkynes is the most Csp important2-Csp coupling method reaction to prepare between arylalkynes aryl or alkenyl and conjugated halides or enynes, triflates whichand terminal are precursors alkynes is for the natural most important products, method pharmaceuticals, to prepare arylalkynes and molecular and conjugatedorganic materials enynes, which(Scheme are 1) [1]. precursors The pioneering for natural works products, of Heck [2] pharmaceuticals, and Cassar [3] in and 1975, molecular using phosphine organic-palladium materials (Schemecatalysts1 at)[ temperatures1]. The pioneering up to 100 works °C, ofwere Heck improved [2] and in Cassar the same [3] in year 1975, by using Sonogashira phosphine-palladium and Hagihara, reportingcatalysts at that temperatures the addition up of to a 100 catalytic◦C, were amount improved of copper(I) in the same accelerates year by the Sonogashira reaction, thus and Hagihara,enabling toreporting achieve thatthe a thelkynylation addition ofat aroom catalytic temperature amount of[4]. copper(I) Therefore, accelerates the Sonogashira the reaction,–Hagihara thus enablingprotocol (moreto achieve often the simply alkynylation known atas room Sonogashira temperature reaction) [4]. Therefore, became the the most Sonogashira–Hagihara popular procedure protocol for the (morealkynylation often simplyof aryl knownor alkenyl as Sonogashira halides [1,5,6 reaction)]. It is interesting became the to most note popular that ma procedureny of the forrecent the developmentsalkynylation of about aryl new or alkenyl catalytic halides systems [1 able,5,6]. to Itcarry is interesting out this reaction to note are that intended many to of be the “copper recent- freedevelopments” processes, about to avoid new catalyticundesirable systems Glaser able-type to alkyne carry outhomocoupling this reaction [7] are and intended to diminish to be “copper-free”environmental processes, contamination, to avoid these undesirable processes Glaser-type however alkyne still homocouplingbeing termed [ 7]as and “Sonogashira to diminish reactionsenvironmental”. contamination, these processes however still being termed as “Sonogashira reactions”. Scheme 1. The general Sonogashira cross cross-coupling-coupling reaction reaction.. Catalysts 2018, 8, x; doi: FOR PEER REVIEW www.mdpi.com/journal/catalysts Catalysts 2018, 8, 202; doi:10.3390/catal8050202 www.mdpi.com/journal/catalysts Catalysts 2018, 8, 202 2 of 39 Catalysts 2018, 8, x FOR PEER REVIEW 2 of 38 From an economical, as well as an environmental, point of view, recovering and reusing the expensive palladium catalystcatalyst results particularlyparticularly interesting.interesting. The The obvious way of recovering the catalyst would be anchoring the catalytic species to a solid support, which would allow its easy separation afterafter the the reaction reaction completion completion just byjust simple by simple filtration, filtration, this topic this being topic considered being considered nowadays anowadays fast-moving a fast research-moving field research [8–12]. field The present[8–12]. The review present shows review recent shows developments recent developments in the Sonogashira in the reactionSonogashira carried reaction out by carried using out solid-supported by using solid palladium-supported catalysts palladium and catalysts reported and from reported 2012 till from the beginning2012 till the of beginning 2018 [13]. Theof 2018 review [13]. has The been review divided has considering been divided the considering different types the ofdifferent supports types for the of palladiumsupports for species. the palladium It is necessary species. to noteIt is that,necessary although to note in many that, cases although the real in catalystmany cases is unknown, the real palladiumcatalyst is (0)unknown, nanoparticles palladium (PdNPs) (0) nanoparticles are generally considered(PdNPs) are to generally be the active considered catalytic species,to be the most active of thecatalyt palladiumic species, complexes most of the being palladium just precursors. complexes being just precursors. 2. Organic Polymer-SupportedPolymer-Supported Palladium Catalysts Organic polymers have been the oldest recoverable supports for palladium species acting as catalyst in Sonogashira reactions, and still manymany new palladium-containingpalladium-containing organic polymers able to catalyze this cross-couplingcross-coupling reactionreaction appear.appear. ItIt isis interesting toto note that almost all these new catalysts can perform the reaction inin aa copper-freecopper-free fashionfashion (Scheme(Scheme2 2).). Scheme 2.2. A generalgeneral copper-freecopper-free Sonogashira cross-couplingcross-coupling reaction between an aryl halide and a terminal alkyne.alkyne. Polystyrene-divinylbenzene resin beads have been the most frequently employed organic Polystyrene-divinylbenzene resin beads have been the most frequently employed organic supports supports for anchoring palladium complexes. Thus, PdNPs supported on a crosslinked polystyrene for anchoring palladium complexes. Thus, PdNPs supported on a crosslinked polystyrene 1 (Figure1) 1 (Figure 1) were used as catalyst in the copper-free Sonogashira coupling of phenylacetylene with were used as catalyst in the copper-free Sonogashira coupling of phenylacetylene with aryl iodides, aryl iodides, bromides and chlorides (Scheme 2), the addition of tetra-n-butylammonium bromide bromides and chlorides (Scheme2), the addition of tetra- n-butylammonium bromide (TBAB) as (TBAB) as nanoparticle stabilizer being necessary in the case of aryl chlorides [14]. The catalyst was nanoparticle stabilizer being necessary in the case of aryl chlorides [14]. The catalyst was recovered by recovered by filtration and reused up to five times in the model reaction between iodobenzene and filtration and reused up to five times in the model reaction between iodobenzene and phenylacetylene phenylacetylene obtaining recycling yields ranging from 88% to 72%. Other case is the obtaining recycling yields ranging from 88% to 72%. Other case is the phenyldithiocarbazate Pd(II) phenyldithiocarbazate Pd(II) complex 2 (Figure 1), which catalyzes the copper-free coupling of aryl complex 2 (Figure1), which catalyzes the copper-free coupling of aryl iodides and bromides, in pyridine iodides and bromides, in pyridine as base and at room temperature under neat conditions (Scheme as base and at room temperature under neat conditions (Scheme2)[ 15]. The supported catalyst 2) [15]. The supported catalyst has been reused up to five
Load more

Recommended publications
  • 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].
    [Show full text]
  • Sonogashira Coupling Reaction in Water Using a Polymer-Supported Terpyridine–Palladium Complex Under Aerobic Conditions
    Trans. Mat. Res. Soc. Japan 40[2] 103-106 (2015) Sonogashira Coupling Reaction in Water Using a Polymer-Supported Terpyridine–Palladium Complex under Aerobic Conditions Toshimasa Suzuka,* Mika Adachi, and Kazuhito Ogihara Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Nishihara Okinawa 903-0213, Japan Fax: 81-098-895-8531, e-mail: [email protected] The palladium-catalyzed coupling reaction between an aryl halide and a terminal alkyne, the so-called Sonogashira coupling reaction, was found to occur in water under copper-free conditions using an amphiphilic polystyrene–poly(ethylene glycol) (PS-PEG) resin-supported palladium–terpyridine complex, giving the corresponding aryl-substituted alkyne in high yield. The PS-PEG resin-supported palladium–terpyridine catalyst was recovered simply by filtering the product mixture under air and could be reused three times with only slightly decreased catalytic activity after each use. Key words: Sonogashira, palladium, terpyridine, water, cross-coupling 1. INTRODUCTION organic solvent or metal-contaminated wastes are The palladium-catalyzed coupling reaction produced; and (2) the presence of oxygen and between an aryl halide and a terminal alkyne, the moisture do not negatively affect the reaction. so-called Sonogashira reaction [1], is recognized These benefits therefore allow the Sonogashira as being the most successful method for forming coupling reaction to be performed meeting the an sp2 carbon–sp3 carbon bond. Since its requirements of “green chemistry”. discovery by Sonogashira and co-workers in 1975, a vast amount of research has been performed cat 1. ( 5mol% Pd) into its synthetic applications and on improving X + R1 R1 the reaction efficiency [2].
    [Show full text]
  • 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.
    [Show full text]
  • Multimetallic Catalysed Radical Oxidative C(Sp3)–H/C(Sp)–H Cross-Coupling Between Unactivated Alkanes and Terminal Alkynes
    ARTICLE Received 2 Jan 2016 | Accepted 19 Apr 2016 | Published 24 Jun 2016 DOI: 10.1038/ncomms11676 OPEN Multimetallic catalysed radical oxidative C(sp3)–H/C(sp)–H cross-coupling between unactivated alkanes and terminal alkynes Shan Tang1, Pan Wang1, Haoran Li1 & Aiwen Lei1,2 Radical involved transformations are now considered as extremely important processes in modern organic synthetic chemistry. According to the demand by atom-economic and sustainable chemistry, direct C(sp3)–H functionalization through radical oxidative coupling represents an appealing strategy for C–C bond formations. However, the selectivity control of reactive radical intermediates is still a great challenge in these transformations. Here we show a selective radical oxidative C(sp3)–H/C(sp)–H cross-coupling of unactivated alkanes with terminal alkynes by using a combined Cu/Ni/Ag catalytic system. It provides a new way to access substituted alkynes from readily available materials. Preliminary mechanistic studies suggest that this reaction proceeds through a radical process and the C(sp3)–H bond cleavage is the rate-limiting step. This study may have significant implications for controlling selective C–C bond formation of reactive radical intermediates by using multimetallic catalytic systems. 1 College of Chemistry and Molecular Sciences, Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, China. 2 National Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, China. Correspondence and requests for materials should be addressed to A.L. (email: [email protected]). NATURE COMMUNICATIONS | 7:11676 | DOI: 10.1038/ncomms11676 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms11676 ubstituted alkynes are fundamental structural motifs in been developed through normal cross-dehydrogenative numerous natural products, bioactive molecules and coupling33 pathway (Fig.
    [Show full text]
  • 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.
    [Show full text]
  • New Trends in C–C Cross-Coupling Reactions: the Use of Unconventional Conditions
    molecules Review New Trends in C–C Cross-Coupling Reactions: The Use of Unconventional Conditions Marta A. Andrade and Luísa M. D. R. S. Martins * Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; [email protected] * Correspondence: [email protected]; Tel.: +35-121-841-9389 Academic Editor: Giuseppe Cirillo Received: 30 October 2020; Accepted: 20 November 2020; Published: 24 November 2020 Abstract: The ever-growing interest in the cross-coupling reaction and its applications has increased exponentially in the last decade, owing to its efficiency and effectiveness. Transition metal-mediated cross-couplings reactions, such as Suzuki–Miyaura, Sonogashira, Heck, and others, are powerful tools for carbon–carbon bond formations and have become truly fundamental routes in catalysis, among other fields. Various greener strategies have emerged in recent years, given the widespread popularity of these important reactions. The present review comprises literature from 2015 onward covering the implementation of unconventional methodologies in carbon–carbon (C–C) cross-coupling reactions that embodies a variety of strategies, from the use of alternative energy sources to solvent- free and green media protocols. Keywords: cross-coupling reactions; microwave irradiation; ultrasounds; mechanochemistry; solvent-free; water; ionic liquids; deep eutectic solvents; sustainability 1. Introduction Cross-coupling reactions have attracted and inspired researchers in the academia and industry for decades, given its significance as a synthetic tool in modern organic synthesis. The continuous interest in cross-coupling reactions, with more than 40 years of history, has been mostly driven by its valuable contributions and applications in the medicinal and pharmaceutical industries.
    [Show full text]
  • 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).
    [Show full text]
  • 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
    [Show full text]
  • A. Discovery of Novel Reactivity Under the Sonogashira Reaction Conditions B. Synthesis of Functionalized Bodipys and BODIPY-Sug
    A. Discovery of novel reactivity under the Sonogashira reaction conditions B. Synthesis of functionalized BODIPYs and BODIPY-sugar conjugates Ravi Shekar Yalagala, M.Phil Department of Chemistry Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Faculty of Mathematics and Science, Brock University St. Catharines, Ontario © 2016 ABSTRACT A. During our attempts to synthesize substituted enediynes, coupling reactions between terminal alkynes and 1,2-cis-dihaloalkenes under the Sonogashira reaction conditions failed to give the corresponding substituted enediynes. Under these conditions, terminal alkynes underwent self-trimerization or tetramerization. In an alternative approach to access substituted enediynes, treatment of alkynes with trisubstituted (Z)- bromoalkenyl-pinacolboronates under Sonogashira coupling conditions was found to give 1,2,4,6-tetrasubstituted benzenes instead of Sonogashira coupled product. The reaction conditions and substrate scopes for these two new reactions were investigated. B. BODIPY core was functionalized with various functional groups such as nitromethyl, nitro, hydroxymethyl, carboxaldehyde by treating 4,4-difluoro-1,3,5,7,8- pentamethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indacene with copper (II) nitrate trihydrate under different conditions. Further, BODIPY derivatives with alkyne and azido functional groups were synthesized and conjugated to various glycosides by the Click reaction under the microwave conditions. One of the BODIPY–glycan conjugate was found to form liposome upon rehydration. The photochemical properties of BODIPY in these liposomes were characterized by fluorescent confocal microscopy. ii ACKNOWLEDGEMENTS I am extremely grateful to a number of people. Without their help, this document would have never been completed. First and foremost, I would like to thank my supervisor and mentor Professor Tony Yan for his guidance and supervision to make the thesis possible.
    [Show full text]
  • 202 Section: B Course Instructor: Dr BK Singh Study Material (Name of T
    Course Name: Methods in Organic Synthesis Paper Number: 202 Section: B Course Instructor: Dr BK Singh Study Material (Name of Topic/Chapter): Organosilicone Compounds, Preparation and applications in organic synthesis; Application of Pd(0) and Pd(II) Complexes in Organic Synthesis- Stille, Suzuki and Sonogashira Coupling, Heck reaction and Negishi Coupling. Dr. BK SINGH, Department of Chemistry, University of Delhi Applications of Pd(0) and Pd(II) complexes in organic synthesis- Heck, Negishi, Suzuki, Stille and Sonogashira Coupling 2010 Nobel Prize in Chemistry awarded jointly to Richard F. Heck, Ei-ichi Negishi, and Akira Suzuki "for palladium-catalyzed cross couplings in organic synthesis" Dr. BK SINGH, Department of Chemistry, University of Delhi Palladium-catalyzed carbon-carbon bond formation via cross coupling The principle of palladium-catalyzed cross couplings is that two molecules are assembled on the metal via the formation of metal-carbon bonds. In this way the carbon atoms bound to palladium are brought very close to one another. In the next step they couple to one another and this leads to the formation of a new carbon-carbon single bond. There are two types of cross-coupling reactions that have become important in organic synthesis. Both reactions are catalyzed by zero valent Pd and both reactions employ an organohalide RX (or analogous compound) as the electrophilic coupling partner. The nucleophilic coupling partner differs in these two reactions. In the first type it is an olefin whereas in the second type it is an organometallic compound R’’M where, M is typically zinc, boron, or tin. Both reactions begin by generating an organopalladium complex RPdX from the reaction of the organic halide with Pd(0).
    [Show full text]
  • Heck Reaction Chem 115
    Myers The Heck Reaction Chem 115 Reviews: Felpin, F.-X.; Nassar-Hardy, L.; Le Callonnec, F.; Fouquet, E.Tetrahedron 2011, 67, 2815–2831. • Pd(II) is reduced to the catalytically active Pd(0) in situ, typically through the oxidation of a Belestskaya, I. P.; Cheprakov, A. V. Chem. Rev. 2000, 100, 3009–3066. phosphine ligand. • Intramolecular: Link, J. T.; Overman, L. E. In Metal-catalyzed Cross-coupling Reactions, Diederich, F., and Pd(OAc)2 + H2O + nPR3 + 2R'3N Pd(PR3)n-1 + O=PR3 + 2R'3N•HOAc Eds.; Wiley-VCH: New York, 1998, pp. 231–269. Gibson, S. E.; Middleton, R. J. Contemp. Org. Synth. 1996, 3, 447–471. Ozawa, F.; Kubo, A.; Hayashi, T. Chemistry Lett. 1992, 2177–2180. • Asymmetric: McCartney, D.; Guiry, P. J. Chem. Soc. Rev. 2011, 40, 5122–5150. • Ag+ / Tl+ salts irreversibly abstract a halide ion from the Pd complex formed by oxidative • Solid phase: addition. Reductive elimination from the cationic complex is probably irreversible. Franzén, R. Can. J. Chem. 2000, 78, 957–962. • Dehydrogenative: • An example of a proposed mechanism involving cationic Pd: Le Bras, J.; Muzart, J. Chem. Rev. 2011, 111, 1170–1214. General transformation: Pd catalyst Ph–Br Ph CH3O2C CH3O2C Pd(II) or Pd(0) catalyst Ag+ R' R–X + R' + HX base R R = alkenyl, aryl, allyl, alkynyl, benzyl X = halide, triflate R' = alkyl, alkenyl, aryl, CO R, OR, SiR 2 3 Pd(II) AgHCO 2 L; 2 e – • Proposed mechanism involving neutral Pd: 3 – reductive elimination AgCO3 Ph–Br oxidative addition Pd(0)L2 Mechanism: Pd catalyst + Ph–Br Ph H–Pd(II)L2 Ph–Pd(II)L2–Br CH3O2C CH3O2C Ph Ag + CH3O2C Pd(II) KHCO + KBr 2 L; 2 e – AgBr 3 syn elimination + halide abstraction Pd(II)L2 reductive elimination oxidative addition H + K2CO3 Ph–Br H Ph–Pd(II)L2 Pd(0)L2 CH3O2C Ph H + Pd(II)L2 H–Pd(II)L2–Br Ph–Pd(II)L2–Br H Ph CH3O2C syn elimination CH3O2C H internal rotation syn addition CH3O2C H Ph CH3O2C Pd(II)L2Br syn addition H Pd(II)L2Br H H CH O C Ph 3 2 Ph CH3O2C H H H Abelman, M.
    [Show full text]
  • Mediated Azide-Alkyne Cycloaddition Reactions Using Chelating Azides Wendy S
    Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2012 Development of Copper(II)-Mediated Azide-Alkyne Cycloaddition Reactions Using Chelating Azides Wendy S. Brotherton Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] THE FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES DEVELOPMENT OF COPPER(II)-MEDIATED AZIDE-ALKYNE CYCLOADDITION REACTIONS USING CHELATING AZIDES By WENDY S. BROTHERTON A Dissertation submitted to the Department of Chemistry and Biochemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy Degree Awarded: Spring Semester, 2012 Wendy S. Brotherton defended this dissertation on December 8, 2011. The members of the supervisory committee were: Lei Zhu Professor Directing Dissertation P. Bryant Chase University Representative Gregory B. Dudley Committee Member Igor V. Alabugin Committee Member Michael G. Roper Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the dissertation has been approved in accordance with university requirements. ii This manuscript is dedicated to my mother for all of her encouragement and sacrifices over the many years of my education. I would also like to dedicate this to my fiancé, Travis Ambrose, who has been so supportive and encouraging throughout this entire process. iii ACKNOWLEDGEMENTS I would like to thank Professor Lei Zhu for his guidance, support and assistance over the course of my graduate studies. I would like to express my gratitude to the past and present members of the Zhu group for their support and friendship over the years: Dr.
    [Show full text]