DOCSLIB.ORG

When Phosphosugars Meet Gold: Synthesis and Catalytic Activities of Phostones and Polyhydroxylated Phosphonite Au(I) Complexes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
When Phosphosugars Meet Gold: Synthesis and Catalytic Activities of Phostones and Polyhydroxylated Phosphonite Au(I) Complexes Article When Phosphosugars Meet Gold: Synthesis and Catalytic Activities of Phostones and Polyhydroxylated Phosphonite Au(I) Complexes Gaëlle Malik, Angélique Ferry and Xavier Guinchard * Received: 23 September 2015 ; Accepted: 20 November 2015 ; Published: 27 November 2015 Academic Editor: Bimal Banik Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Université Paris-Sud, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette cedex, France; [email protected] (G.M.); [email protected] (A.F.) * Correspondence: [email protected]; Tel.: +33-1-69-82-30-66 Abstract: The synthesis and characterization of P-chiral phosphonite-, phosphonate- and thiophosphonate-Au(I) complexes are reported. These novel ligands for Au(I) are based on glycomimetic phosphorus scaffolds, obtained from the chiral pool. The catalytic activities of these complexes are shown in the cyclization of allenols and the hydroamination of 2-(2-propynyl)aniline combined with an organocatalyzed reduction to the corresponding 2-phenyl tetrahydroquinoline. All described gold complexes present excellent catalytic activities. Keywords: gold catalysis; phosphosugars; catalysis; heterocycles; P-stereogeny 1. Introduction One of the major advances of the 21th century in organic chemistry is undoubtedly the increased importance of gold catalysis. Long believed to be useless for catalysis, gold complexes have emerged as powerful tools for the catalysis of myriads of reactions [1–9]. In particular, the gold tolerance towards air, moisture and numerous chemical functionalities renders the use of these catalysts very convenient. However, the bicoordinate linear geometry of gold(I) complexes makes the control of the asymmetry difficult, the chiral ligand being placed in a distal position to the reactive cationic center. Asymmetric approaches have been developed using chiral ligands [10–14], such as chiral phosphines [12,15,16], phosphoramidites [11,17], acyclic diaminocarbenes [18–21], NHCs [22,23], phospha-helicenes [24–26] or phosphate counterions [27,28]. Most of these ligands are based on BINOL, TADDOL and related scaffolds. On the other hand, chiral carbohydrate-type ligands are becoming attractive for asymmetric catalytic purposes, in particular due to their broad availability from the chiral pool, and they have thus been used as ligands in a wide range of catalytic transformations [29–38]. Surprisingly, to the best of our knowledge, carbohydrates have not been used as ligands for gold, aside from a thioglycoside gold complex developed for biological purposes [39]. In the course of a project aiming at the synthesis of novel glycomimetics [40–44], we recently reported the synthesis of various phosphosugar derivatives bearing anomeric phosphorus functions such as phosphonites 1 and phosphonic acid 2 obtained from the corresponding phosphonate esters (Scheme1, Equation (1)) [40,41]. More recently, we disclosed the synthesis of configurationally stable carbohydrate-based P-chiral thiophosphonic acids 3 and their use as organocatalysts in the asymmetric reduction of 2-phenylquinoline (4) to 2-phenyltetrahydroquinoline (5) via asymmetric hydrogen transfer (Scheme1, Equation (2)) [45,46]. In particular, we could demonstrate the Molecules 2015, 20, 21082–21093; doi:10.3390/molecules201219755 www.mdpi.com/journal/molecules Molecules 2015, 20, 21082–21093 dramatic importance of the configuration of the phosphorus atom on the stereochemical outcome Molecules 2015, 20, page–page of the reaction. Molecules 2015, 20, page–page SchemeSchemeScheme 1. 1. 1.Previously PreviouslyPreviously reportedreported results.results results. In thisIn paper, Inthis this paper, we paper, report we report we the report the synthesis synthesis the synthesis of of novel novel of gold novel complexes complexes gold complexes based based on based theon thescaffolds on scaffolds the scaffolds1–3 (Scheme 1–3 1(Scheme–3 1). 1). Hence,Hence, the(Scheme synthesis the 1synthesis). Hence, of chiral of the chiral synthesis phosphonates, phosphonates, of chiral phosphonates,thio thiophosphonates thiophosphonates and and phosphonites phosphonites and phosphonites gold goldcomplexes complexes gold are are reported,reported,complexes along along with are with reported,the theevidence evidence along withof of their thetheir evidencecatalytic catalytic of activities.activities. their catalytic activities. 2. Results2. Results and and Discussion Discussion 2. Results and Discussion We initiated our study with the synthesis of two novel P-chiral phosphonite gold complexes We initiated our study with the synthesis of two novel P-chiral phosphonite gold complexes 6a 6a and 6b. For this purpose, the gluco- and manno- phosphonites 1a and 1b [41], both bearing Weand initiated 6b. For this our purpose, study with the gluc theo- synthesis and manno- of phosphonitestwo novel P-chiral 1a and 1bphosphonite [41], both bearing gold complexesan axial 6a an axial (α-configured) P-OEt bond, were reacted in the presence of sodium tetrachloroaurate and and 6b(α. -configured)For this purpose, P‒OEt thebond, gluc wereo- and reacted manno- in phosphonitesthe presence of1a sodiumand 1b [41],tetrachloroaurate both bearing and an axial 2,2’-dithioethanol, acting as an internal Au(III) to Au(I) reductant (Scheme2). The corresponding 2,2’-dithioethanol, acting as an internal Au(III) to Au(I) reductant (Scheme 2). The corresponding Au(I) (α-configured)Au(I) complexes P‒OEt bond,6a and were6b were reacted obtained in inthe 94% presence and 88% of yield, sodium respectively. tetrachloroaurate Only the and 2,2’-dithioethanol,complexesα-diastereomers 6a actingand were6b as were observed,an internalobtained demonstrating Au(III)in 94% andto theAu(I) 88% configurational yield,reductant respectively. (Scheme stability Only of 2). the Thethe phosphorus αcorresponding-diastereomers atom. Au(I) complexeswereThese observed,6a derivativesand 6b demonstrating were appeared obtained fullythe configurational stablein 94% to and column 88%stability chromatography yield, of the respectively. phosphorus on silica atom. Only gel and These the storage, αderivatives-diastereomers but appeared fully stable to column chromatography on silica gel and storage, but their oily nature did not were observed,their oily demonstrating nature did not allowthe configurational the determination stability of X-ray of diffraction the phosphorus crystallographic atom. These structures. derivatives allowTo thethe bestdetermination of our knowledge, of X-ray thesediffraction structures crystallo constitutegraphic the structures. first examples To the of best P-chiral of our phosphonite knowledge, appeared fully stable to column chromatography on silica gel and storage, but their oily nature did not thesegold structures complexes constitute and in a the more first general examples manner, of P-chiral one of the phosphonite rare examples gold of complexes gold complexes and in with a more a allow thegeneralphosphonite determination manner, ligand one ofof [39 X-raythe,47 –rare51 diffraction]. examples of crystallo gold complexesgraphic with structures. a phosphonite To the ligand best of [39,47–51]. our knowledge, these structures constitute the first examples of P-chiral phosphonite gold complexes and in a more general manner, one of the rare examples of gold complexes with a phosphonite ligand [39,47–51]. SchemeScheme 2. 2. FormationFormation of of P-chiral P-chiral phosphonite Au(I)Au(I) complexes.complexes. WeWe next next turned turned our our attention attention to to the the use use of P-chiral phosphonitephosphonite goldgold complexescomplexes 6 6in in the the gold-catalyzedgold-catalyzed cyclization cyclization of ofallenol allenol 7 leading7 leading to tetrahydrofuran to tetrahydrofuran 8. The8. The catalytic catalytic activities activities of these of Scheme 2. Formation of P-chiral phosphonite Au(I) complexes. complexesthese complexes as well as as the well induction as the inductionof asymmetry of asymmetry generated generatedby these original by these ligands original were ligands determined. were Wedetermined. initiated our We study initiated using our the study manno-configured using the manno-configured gold complex gold6a. After complex activation6a. After by activationAgOTs, the Wetarget next tetrahydrofuran turned our 8 attentionwas obtained to inthe 90% use yield of and P-chiral 9% ee (Table phosphonite 1, entry 1). gold We then complexes screened the6 in the gold-catalyzedeffect of the cyclization silver salt by of using allenol successively 7 leading AgSbF to21083 tetrahydrofuran6, AgBF4, AgClO4 and 8. AgOBzThe catalytic (Table 1, activities entries 2–5). of these complexesIn most as wellcases, as 8 thewas inductionobtained with of asymmetry good yields, gene but withrated moderate by these enantioselectivities original ligands were (2%–7% determined. ee). We initiatedThe corresponding our study usingglucophosphonite the manno-configured gold complex 6bgold was complex next investigated, 6a. After inactivation order to determine by AgOTs, the target thetetrahydrofuran influence of the 8C2 was configuration obtained onin the90% stereoch yield emicaland 9% outcome ee (Table of the 1, reactionentry 1). and We on then the catalytic screened the activity. Using the same set of silver salts, the tetrahydrofuran 8 was obtained in good yields (Table 1, effect of the silver salt by using successively AgSbF6, AgBF4, AgClO4 and AgOBz (Table 1, entries 2–5). entries 6–9), except when silver benzoate was used (Table 1, entry 10), and moderate
Load more

Recommended publications
  • Catalytic Ethylene Dimerization and Oligomerization Speiser Et Al
    Acc. Chem. Res. 2005, 38, 784-793 reaktion)2 of ethylene, nickel salts could modify the nature Catalytic Ethylene Dimerization of the products from R-olefins to 1-butene. This phenom- and Oligomerization: Recent enon became known in the literature as ªthe nickel effectº1,3 and led to the discovery of the ªZiegler catalysisº4 Developments with Nickel and to the remarkable chemistry developed by Wilke and 5 others over decades. The selective synthesis of C4-C20 Complexes Containing linear R-olefins has become a topic of considerable P,N-Chelating Ligands interest in both academia and industry owing to their growing demand most notably as comonomers with ² ,² FREDY SPEISER, PIERRE BRAUNSTEIN,* AND ethylene [C4-C8 to yield branched linear low-density LUCIEN SAUSSINE³ polyethylene (LLDPE) with impressive rheological and Laboratoire de Chimie de Coordination (UMR 7513 CNRS), mechanical properties6], for the synthesis of poly-R-olefins Universite Louis Pasteur, 4 rue Blaise Pascal, F-67070 and synthetic lubricants (C ), as additives for high-density Strasbourg CeÂdex, France, and Institut Franc¸ais du PeÂtrole, 10 Direction Catalyse et SeÂparation, IFP-Lyon, BP 3, F-69390 polyethylene production and for the production of plas- 7-9 Vernaison, France ticizers (C6-C10) and surfactants (C12-C20). The annual 8 Received February 14, 2005 worldwide consumption of polyolefins is close to 10 tons. Because the demand for linear R-olefins is growing faster - × 6 ABSTRACT in the C4 C10 range (a ca. 2.5 10 tons/year market) than Catalytic ethylene oligomerization represents a topic of consider- in the C12+ range, the selective formation from ethylene able current academic and industrial interest, in particular for the of specific shorter chain R-olefins, which could circumvent R - production of linear -olefins in the C4 C10 range, whose demand the typical, broad Schulz-Flory distributions observed in is growing fast.
    [Show full text]
  • Some Transition Metal Complexes of Trivalent Phosphorus Esters
    AN ABSTRACT OF THE THESIS OF HARRY VAUGHN STUDER for the MASTER OF SCIENCE (Name) (Degree) inCHEMISTRY (Inorganic) presented on ///( (Major) / (Date') Title: SOME TRANSITION METAL COMPLEXES OF TRIVALENT PHOSPHORUS ESTERS Redacted for Privacy Abstract approved: Dr. In T. Yoke r The ligands in the series EtnP(OEt)3_11, n = 0 - 3,all form pseudotetrahedral high-spin bis -complexes with cobalt (II) chloride. Magnetic, spectrophotometric, conductivity, and molecular weight data show that the phosphorus ester ligands (but not the phosphine) also form five-coordinate low-spin tris-complexes; these can be isolated with the phosphonite and phosphinite ligands, while the existence of the tris -phosphite is marginal.At cobalt (II) to phosphorus ester mole ratios of 1:2, a mixture of species is present in all cases.All are non-conducting in nitrobenzene. The ester complexes are much more susceptible to autoxidation than is the phosphine complex. Some Transition Metal Complexes of Trivalent Phosphorus Esters by Harry Vaughn Studer A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science June 1972 APPROVED: Redacted for Privacy Profes of Chemi str y / in crge of major Redacted for Privacy Head of Department of Chemistry Redacted for Privacy Dean of Graduate School Date thesis is presented Typed by Donna Olson f arry Vatighn Studer ACKNOWLEDGEMENTS The author wishes to thank his research advisor, Dr. John T. Yoke, for his expert direction of this research, for his patience, and for the opportunity of learning through association with him. Acknowledgement is made to the donors of the Petroleum Re- search Fund, administered by the American Chemical Society, for the support of this work.
    [Show full text]
  • Applications of Boronic Acids in Organic Synthesis
    Applications of Boronic Acids in Organic Synthesis A dissertation presented by Pavel Starkov in partial fulfilment of the requirements for the award of the degree of DOCTOR OF PHILOSOPHY at UNIVERSITY COLLEGE LONDON Department of Chemistry Christopher Ingold Laboratories University College London 20 Gordon Street WC1H 0AJ London Declaration This dissertation is the result of my own work. Where information has been derived from other sources it has been clearly indicated so and acknowledged accordingly. /Pavel Starkov/ ii Abstract This thesis describes progress on the application of boronic acids and borate esters as catalysts and reagents in synthetic organic synthesis, focusing on two areas: one-pot enolate formation/aldol reactions and amide bond formation. Chapter 1 introduces the reader to boronic acids and derivatives thereof, their methods of preparation and their use in synthetic organic chemistry as reactants, reagents and catalysts. Chapter 2 covers current chemical methods and cellular alternatives for amide bond formation. Here, we also discuss our use of boron reagents for the activation of carboxylic acids as well as amides. Chapter 3 introduces a new concept in catalytic aldol reactions, i.e. an alternative strategy to access boron enolates in situ. The work covers successful demonstration of the feasibility of such an approach on an intramolecular system. A novel variation of aerobic Chan–Evans– Lam coupling, an intramolecular coupling of an aliphatic alcohol with a boronic acid using catalytic copper, is also introduced Chapter 4 builds on our observations on gold catalysis and especially that in relation to electrophilic halogenations. Chapter 5 contains full details of the experimental procedures.
    [Show full text]
  • Redox-Responsive Phosphonite Gold Complexes in Hydroamination Catalysis† Cite This: Chem
    Showcasing research from the groups of Jan Paradies As featured in: from the University of Paderborn and Frank Breher from the Karlsruhe Institute of Technology (KIT). Volume 55 Number 37 10 May 2019 Pages 5297–5396 Redox-responsive phosphonite gold complexes in ChemComm Chemical Communications hydroamination catalysis rsc.li/chemcomm Very high activities were observed in the redox-induced hydroamination of alkynes by employing a redox-active gold(I) complex featuring a phosphonite-based ligand. Very low catalyst loadings (down to 10 ppm) and very mild conditions (25 °C) were used. ISSN 1359-7345 COMMUNICATION Kotaro Satoh, Masami Kamigaito et al . Cooperative reduction of various RAFT polymer terminals using hydrosilane and thiol via polarity reversal catalysis See Jan Paradies, Frank Breher et al ., Chem . Commun ., 2019, 55 , 5323. rsc.li/chemcomm Registered charity number: 207890 ChemComm View Article Online COMMUNICATION View Journal | View Issue Redox-responsive phosphonite gold complexes in hydroamination catalysis† Cite this: Chem. Commun., 2019, 55,5323 Eva Deck,a Hanna E. Wagner,a Jan Paradies *b and Frank Breher *a Received 21st February 2019, Accepted 20th March 2019 DOI: 10.1039/c9cc01492f rsc.li/chemcomm Very high activities were observed in the redox-induced hydroamination important structural features of these ligands is the weak – of alkynes by employing a redox-active gold(I)complexfeaturingan for catalyst stability nonetheless crucial – arene p-interactions electron-deficient, terphenyl-substituted phosphonite-based ligand. with the metal centre. In recent years, elegant variations of The hydroamination proceeds roughly two-fold faster with the in situ Buchwald-type biaryl phosphines have been reported by various 7–10 Creative Commons Attribution 3.0 Unported Licence.
    [Show full text]
  • Asymmetric Transfer Hydrogenation of Arylketones Catalyzed by Enantiopure Ruthenium(II)/Pybox Complexes Containing Achiral Phosphonite and Phosphinite Ligands
    molecules Article Asymmetric Transfer Hydrogenation of Arylketones Catalyzed by Enantiopure Ruthenium(II)/Pybox Complexes Containing Achiral Phosphonite and Phosphinite Ligands Miguel Claros, Eire de Julián, Josefina Díez, Elena Lastra and M. Pilar Gamasa * Departamento de Química Orgánica e Inorgánica-IUQOEM (Unidad Asociada al CSIC), Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Oviedo, E-33006 Oviedo, Principado de Asturias, Spain; [email protected] (M.C.); [email protected] (E.d.J.); [email protected] (J.D.); [email protected] (E.L.) * Correspondence: [email protected]; Fax: +34-985103446 Academic Editor: Rafael Chinchilla Received: 28 January 2020; Accepted: 18 February 2020; Published: 23 February 2020 i Abstract: A family of complexes of the formula trans-[RuCl2(L)(R-pybox)] (R-pybox = (S,S)- Pr-pybox, (R,R)-Ph-pybox, L = monodentate phosphonite, PPh(OR)2, and phosphinite, L = PPh2(OR), ligands) were screened in the catalytic asymmetric transfer hydrogenation of acetophenone, observing a strong influence of the nature of both the R-pybox substituents and the L ligand in the process. The best results were obtained with complex trans-[RuCl2{PPh2(OEt)}{(R,R)-Ph-pybox}] (2c), which provided high conversion and enantioselectivity (up to 96% enantiomeric excess, e.e.) for the reduction of a variety of aromatic ketones, affording the (S)-benzylalcohols. Keywords: asymmetric catalysis; transfer hydrogenation; alcohols; ruthenium; pybox; phosphonite ligands; phosphinite ligands 1. Introduction Asymmetric transfer hydrogenation (ATH) of prochiral ketones catalyzed by transition metal complexes, displaying well designed chiral ligands, is currently recognized as a powerful and versatile tool to access enantiopure alcohols [1–13].
    [Show full text]
  • Processing Stabilising Efficiency and Reaction Mechanisms of Curcumin In
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Repository of the Academy's Library POLYMER DEGRADATION AND STABILITY Volume 118, August 2015, Pages 17–23 doi:10.1016/j.polymdegradstab.2015.04.006 http://www.sciencedirect.com/science/article/pii/S0141391015001299 Efficiency of curcumin, a natural antioxidant, in the processing stabilization of PE: concentration effects Balázs Kirschweng1,2, Dóra Tátraaljai1,2, Enikő Földes1,2*, Béla Pukánszky1,2 1Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1519 Budapest, P.O. Box 286, Hungary 2Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box 91, Hungary * Corresponding author. Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1519 Budapest, P.O. Box 286, Hungary. E-mail: [email protected] 1 Abstract The stabilising efficiency of curcumin was studied in polyethylene during processing and under oxygen at high temperature. The effect of the natural antioxidant was investigated at concentrations of 0 to 1000 ppm in combination with a phosphonite secondary antioxidant (Sandostab P-EPQ) of 1000 and 2000 ppm, respectively. The polymer was homogenized with the additives then processed by six consecutive extrusions taking samples after each processing step. The samples were characterized by FT-IR spectroscopy, melt flow index, colour, and OIT measurements. Compared to the effect of pure phosphorous antioxidant, the melt stability of PE is increased already at 5 ppm curcumin content.
    [Show full text]
  • Phosphonite Mediated 1,3-Dipolar Cycloaddition: a Route to Polycyclic 2- Pyrrolines from Imines, Acid Chlorides and Alkenes
    Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2013 Phosphonite Mediated 1,3-Dipolar Cycloaddition: A Route to Polycyclic 2- Pyrrolines from Imines, Acid Chlorides and Alkenes Marie S. T. Morin, Sara Aly and Bruce A. Arndtsen* 801 Sherbrooke St. W., Department of Chemistry, McGill University Montreal, Quebec H3A 2K6 Canada Supporting Information Page I. General Procedures 1 II. Imine Synthesis 2-4 III. Synthesis of Pyrrolines 3 5-8 IV. Synthesis of Pyrrolidines 4 9-10 V. Synthesis of pyrrole 5k 10 VI. References 10-11 VII. 1H and 13C NMR Spectra 12-42 I. General Procedures All reactions were performed under an inert nitrogen atmosphere in either a Vacuum Atmospheres 553-2 dry box or using Schlenk techniques. Reagents were purchased from commercial sources and used as received. Solid PPh3 and PCy3 were dried by heating at 120˚C under high vaccum. Liquid P(OCH2CF3)3, P(OPh)3 and P(NMe2)3 were dried over 4 A molecular sieves. (2-catechyl)PPh was prepared by a literature procedure.1 Aldehyde precursors to imines 2 3 4 2a,b,f-m, 2c,e and 2d were prepared by literature procedures. CDCl3 and CD3CN were distilled from CaH2 under nitrogen. Dichloromethane and diethyl ether were dried via filtration through activated molecular sieves (MBraun SPS). 1H and 13C NMR spectra were recorded on Varian Mercury 300 MHz, 400 MHz and Unity 500 MHz spectrometers. The stereochemistry of the pyrroline and pyrrolidine products was determined by NoE NMR experiments (3a, 3f, 4a and 4c), and comparison to literature reported compounds.6 1 Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2013 II.
    [Show full text]
  • Organophosphorus Chemistry (Kanda, 2019)
    Baran lab Group Meeting Yuzuru Kanda Organophosphorus Chemistry 09/20/19 bonding and non-bonding MOs of PH3 bonding and non-bonding MOs of PH5 # of R P(III) ← → P(V) O P P R R R R R R phosphine phosphine oxide D3h C3v C2v O O JACS. 1972, 3047. P P P P R NH R OH R OH R NH Chem. Rev. 1994, 1339. R 2 R R R 2 D C phosphineamine phosphinite phosphinate phosphinamide 3h 4v O O O R P R P R P R P R P R P NH2 NH2 OH OH NH2 NH2 H2N HO HO HO HO H2N phosphinediamine phosphonamidite phosphonite phosphonate phosphonamidate phosphonamide O O O O H N P P P P P P P P 2 NH HO HO HO HO HO HO H2N H N 2 NH2 NH2 OH OH NH2 NH2 NH2 2 H2N HO HO HO HO H2N H2N phosphinetriamine phosphorodiamidite phosphoramidite phosphite phosphate phosphoramidate phosphorodiamidate phosphoramide more N O more O Useful Resources more N P P P Corbridge, D. E. C. Phosphorus: Chemistry, Biochemistry and H OH H H H H H H H Technology, 6th ed.; CRC Press Majoral, J. P. New Aspects In Phosphorus Chemistry III.; Springer phosphinous phosphane phosphane Murphy, P. J. Organophosphorus Reagents.; Oxford acid oxide Hartley, F. R. The chemistry of organophosphorus compounds, O O volume 1-3.; Wiley P P P Cadogan. J. I. G. Organophosphorus Reagents in Organic H OH H OH H OH HO HO H Synthesis.; Academic Pr phosphonate phosphonus acid phosphinate Not Going to Cover ↔ (phosphite) Related GMs Metal complexes, FLP, OPV Highlights in Peptide and Protein NH S R • oxidation state +5, +4, +3, +2, +1, 0, -1, -2, -3 Synthesis (Malins, 2016) R P-Stereogenic Compounds P P R P • traditionally both +3 and -3 are written as (III) R • 13/25th most abundant element on the earth (Rosen, 2014) R • but extremely rare outside of our solar system Ligands in Transition Metal phosphine imide phosphine sulfide phosphorane Catalysis (Farmer, 2016) Baran lab Group Meeting Yuzuru Kanda Organophosphorus Chemistry 09/20/19 Me P Me Me Low-Coordinate Low Oxidation State P tBu tBu P P phosphaalkyne R N P PivCl 2 P Me Cl TMS OTMS NaOH R = tBu Nb N tBu PTMS3 P O H O P NR2 then Na/Hg tBu N -2 Nb tBu R2N Me Nb N tBu 5x10 mbar, 160 ºC NR2 95% R2N Me N O 1.
    [Show full text]
  • New One-Pot Methods for Preparation of Cyclohexanecarbonitrile—Green Chemistry Metrics Evaluation for One-Pot and Similar Multi-Step Syntheses
    Green and Sustainable Chemistry, 2014, 4, 70-79 Published Online May 2014 in SciRes. http://www.scirp.org/journal/gsc http://dx.doi.org/10.4236/gsc.2014.42011 New One-Pot Methods for Preparation of Cyclohexanecarbonitrile—Green Chemistry Metrics Evaluation for One-Pot and Similar Multi-Step Syntheses Jan Simbera, Richard Sevcik, Pavel Pazdera Centre for Syntheses at Sustainable Conditions and Their Management, Faculty of Science, Masaryk University, Brno, Czech Republic Email: [email protected] Received 14 March 2014; revised 14 April 2014; accepted 22 April 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Three new multi-step one-pot processes for high-yielding cyclohexanecarbonitrile synthesis start- ing from cyclohexanone were developed for industrial application. In contrast to the current syn- thetic process, all of the processes described were designed to proceed completely in methanol as a uniform solvent and the key oxidation step can be realized either as stoichiometric or catalytic. Atom efficiency of processes is relatively advanced with high regioselectivity, reaction by-pro- ducts are either from environmental pool—carbon dioxide and nitrogen—or they can be reused— sodium chloride. Solvent—methanol—and other auxiliaries—cyclohexane, copper catalyst—can be reused after recycling as well. EcoScale for all three designed processes was evaluated and compared with current synthesis described in the past. Green chemistry metrics, including newly introduced evaluative tool—Sustainability Index of the Synthesis (SIS), were applied to evaluate design of described one-pot syntheses.
    [Show full text]
  • Synthesis and Characterisation of MOP-Phosphonite Complexes and Their Applications in Asymmetric Catalysis
    Synthesis and Characterisation of MOP-phosphonite Complexes and their Applications in Asymmetric Catalysis PhD Thesis Submitted by James T. Fleming Supervisor: Dr Lee J. Higham School of Chemistry Faculty of Science, Agriculture and Engineering Newcastle University Newcastle upon Tyne United Kingdom Abstract In this thesis we report our synthesis of user-friendly, chiral phosphonite ligands, based upon Hayashi’s MOP backbone, and their application in asymmetric catalytic transformations. Chapter 1 gives an introduction to organophosphorus ligands in catalysis and the use of air-stable primary phosphines as precursors in the synthesis of functionalised phosphorus compounds. Chapter 2 details our synthesis and characterisation of the enantiopure MOP-phosphonite ligands (S)-28a and (R)-28b containing two phenoxy substituents, (S)-29a and (R)-29b with a biphenoxy moiety and (S)-30a and (R)-30b with a 3,3'-dimethylbiphenoxy group. These ligands are proven to be very successful in high-yielding, regio- and enantioselective palladium-catalysed hydrosilylation reactions of substituted styrenes, affording important chiral secondary alcohols, with (S)-30a achieving ees of up to 95%. In-depth NMR studies reveal the hemilabile nature of the bonding of (R)-30a in a palladium 2-methylallyl complex, where the phosphonite ligand acts as a chelating P,C-π-donor. In Chapter 3 we compare our series of novel ligands via experimental and computational methods in an effort to quantify their differing structural and electronic profiles. Four [Rh(LP)(η2:η2-cod)Cl] and two P [Rh(L )2]BF4 complexes were synthesised and characterised by NMR spectroscopy, HRMS and, in all but one case, by X-ray crystallography.
    [Show full text]
  • Alkanes and Tri(Boryl)Alkenes: the Versatile Reagents
    molecules Review Tri(boryl)alkanes and Tri(boryl)alkenes: The Versatile Reagents Oriol Salvadó and Elena Fernández * Department Química Física i Inorgànica, University Rovira i Virgili, 43007 Tarragona, Spain; [email protected] * Correspondence: [email protected] Received: 26 March 2020; Accepted: 8 April 2020; Published: 10 April 2020 Abstract: The interest of organoboron chemistry in organic synthesis is growing, together with the development of new and versatile polyborated reagents. Here, the preparation of 1,1,1-tri(boryl)alkanes, 1,2,3-tri(boryl)alkanes, 1,1,2-tri(boryl)alkanes, as well as 1,1,2-tri(boryl)alkenes as suitable and accessible polyborated systems is demonstrated as being easily applied in the construction of new carbon-carbon and carbon-heteroatom bonds. Synthetic procedures and limitations have been collected to demonstrate the powerful strategies to construct selective molecules, taking advantages of the easy transformation of carbon-boron bond in multiple functionalities, under the total control of chemo- and stereoselectivity. Keywords: 1,1,1-tri(boryl)alkanes; 1,2,3-tri(boryl)alkanes; 1,1,2-tri(boryl)alkanes; 1,1,2-tri(boryl) alkenes; synthetic approaches; synthetic applications 1. Introduction The possibility of preparing a compound that contains three C-B bonds within its formula enhances the power towards polyfunctionalization strategies in a sequential manner. The fact that the three boryl units can be bonded to the same C or different carbons of the same single compound opens a large number of possibilities to construct a new functional product, especially from the perspective that the presence of more than one boryl group contributes to the stabilization of the intermediate carbanions formed, facilitating the transformation of the C-B bond, even under room temperature conditions.
    [Show full text]
  • Potential Chemical Transformation of Phosphinic Acid Derivatives and Their T Applications in the Synthesis of Drugs ⁎ Moaz M
    Bioorganic Chemistry 90 (2019) 103039 Contents lists available at ScienceDirect Bioorganic Chemistry journal homepage: www.elsevier.com/locate/bioorg Potential chemical transformation of phosphinic acid derivatives and their T applications in the synthesis of drugs ⁎ Moaz M. Abdoua,b, , Rasha A. El-Saeedc a Egyptian Petroleum Research Institute, Nasr City, P.O. 11727, Cairo, Egypt b Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK c Department of Chemistry, Faculty of Science, Mansoura University, ET-35516 Mansoura, Egypt ARTICLE INFO ABSTRACT Keywords: The chemical transformation of phosphinic acid is a well-considered mature area of research on account of the Kabachnik–Fields reaction historical significant reactions such as Kabachnik–Fields, Mannich, Arbuzov, Michaelis–Becker, etc. Considerable Hydrophosphinylation advances have been made over last years especially in metal-catalyzed, free-radical processes and asymmetric Phospha-Mannich Reaction synthesis using catalytic enantioselective. As a result, the aim of this synopsis is to make the reader familiar with Hirao cross-coupling reactions advances in the approaches of phosphinic acids toward the synthesis of highly functionalized and valuable Amidoalkylation buildings blocks. Another purpose of this survey is to provide the current status of the applications of phosphinic Michael addition Synthesis of drugs acids in the synthesis of drugs. 1. Introduction chemistry in organic synthesis, exhaustive studies have been devoted to finding out convenient and efficient reactions [18–26]. During the past Among a wide range of interesting phosphorous compounds, the decades, several types of reactions leading to phosphinic acids have phosphinic acid family has attracted recognition as being one of the been reported, such as Kabachnik–Fields, Mannich, Arbuzov, Michae- versatile synthons with useful medicinal and therapeutic properties lis–Becker, etc.
    [Show full text]