DOCSLIB.ORG

Proazaphosphatrane and Bench-Stable Carbon-Based Lewis Acids in Frustrated Lewis Pair Chemistry

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Proazaphosphatrane and Bench-Stable Carbon-Based Lewis Acids in Frustrated Lewis Pair Chemistry Proazaphosphatrane and Bench-Stable Carbon-Based Lewis Acids in Frustrated Lewis Pair Chemistry by Gabriel Nicholas Jun Hao Wee A thesis submitted in conformity with the requirements for the degree of Master of Science Department of Chemistry University of Toronto © Copyright by Gabriel N. J. H. Wee 2019 Proazaphosphatrane and Bench-Stable Carbon-Based Lewis Acids in Frustrated Lewis Pair Chemistry Gabriel Nicholas Jun Hao Wee Master of Science Department of Chemistry University of Toronto 2019 Abstract B(C6F5)3 and P(MeNCH2CH2)3N form a classical Lewis adduct, (C6F5)3BP(MeNCH2CH2)3N. Although the adduct does not exhibit spectroscopic evidence of dissociation into its constituent Lewis acid and base, products of frustrated Lewis pair (FLP) addition reactions are observed with PhNCO, PhCH2N3, PhNSO, and CO2. Recently, a bench-stable trityl cation and P(MeNCH2CH2)3N were also found to form a classical Lewis adduct that does not exhibit spectroscopic evidence of dissociation. This adduct was able to carry out the heterolytic splitting of H2. Interestingly, when this and other newly synthesized bench-stable trityl cations were combined with phosphine bases such as P(t-Bu)3 and P(o-tol)3, FLPs capable of heterolytic splitting of H2 were generated and, in at least one case, reversible activation of H2 was observed. These recent findings open avenues towards the application of bench-stable carbon-based Lewis acids for FLP mediated hydrogenation. ii Acknowledgments I would like to express my sincere gratitude to my research supervisor, Prof. Douglas Stephan for his patience, support, guidance and giving me the opportunity to work and be a part of such a wonderful research group. Thank you for taking me on as a student and providing directions for me to grow as a researcher. I am very grateful for the opportunity to work in your lab. My time in your lab has undoubtedly made me a better scientist. I would also like to thank Prof. Datong Song for taking the time to review this thesis. I am also incredibly fortunate to have had the opportunity to work with some amazing collaborators in the group. I would like to thank Dr. Timothy Johnstone (now Prof.) for helping me get started and established in the lab. I am very grateful for your patience and willingness to help me with chemistry and provide feedback. My experience working closely with you has taught me how to be a better scientist. I would also like to thank Eliar Mosaferi (now Dr.) for his help on solving structures and helpful discussions. Your advice and inputs are truly appreciated. I would also like to extend my gratitude to all members of the Stephan research group for their support and encouragement throughout this degree, especially Karlee Bamford, Alex Waked, Ryan Andrews, Christopher Major, James LaFortune, Jolie Lam and Alvaro Briceno-Strocchia. Thank you for making my time in the lab immensely enjoyable. Last but not least, I would like to thank my family and friends for their support and encouragement throughout this degree. This would not have been possible without your love and support. iii Table of Contents Abstract ........................................................................................................................................... ii Acknowledgments ......................................................................................................................... iii Table of Contents ........................................................................................................................... iv List of Figures ................................................................................................................................. vi List of Schemes ............................................................................................................................ vii List of Symbols and Abbreviations ................................................................................................ ix Chapter 1 ......................................................................................................................................... 1 Introduction ..................................................................................................................................... 1 1.1 Frustrated Lewis Pair Chemistry ........................................................................................... 1 1.2 Group 14 Lewis Acids ........................................................................................................... 7 1.3. Scope of Thesis ................................................................................................................... 11 Chapter 2 ....................................................................................................................................... 13 Accessing Frustrated Lewis Pair Chemistry from a Spectroscopically Stable and Classical Lewis Adduct ........................................................................................................................................... 13 2.1 Introduction ......................................................................................................................... 13 2.2 Results and Discussion ........................................................................................................ 15 2.3 Conclusion ........................................................................................................................... 24 2.4 Experimental Section ........................................................................................................... 24 2.4.1 General Consideration .................................................................................................. 24 2.4.3 X-ray crystallography ................................................................................................... 31 Chapter 3 ....................................................................................................................................... 33 Bench-Stable Carbon-Based Lewis Acids in Frustrated Lewis Pair Chemistry ........................... 33 3.1 Introduction ......................................................................................................................... 33 3.2 Results and Discussion ........................................................................................................ 39 3.2.1 Reactivity of Bench-Stable Trityl Cations with Proazaphosphatrane .......................... 39 3.2.2 Reactivity of Bench-Stable Trityl Cations with Phosphines ........................................ 49 3.3 Conclusion ........................................................................................................................... 55 3.4 Experimental Section ........................................................................................................... 56 3.4.1 General Consideration .................................................................................................. 56 3.4.2 Synthesis of Starting Materials ..................................................................................... 57 3.4.3 X-ray crystallography ................................................................................................... 60 References ..................................................................................................................................... 62 iv List of Tables Table 1: X-ray crystallographic data for 2-1 – 2-5. ....................................................................... 32 Table 2. X-ray crystallographic data for 3-1 ................................................................................. 61 v List of Figures Figure 1: Frontier molecular orbital depiction of a classical Lewis pair reactivity resulting in adduct formation .............................................................................................................................. 1 Figure 2: Frontier molecular orbital depiction of a frustrated Lewis pair reactivity resulting in no adduct formation .............................................................................................................................. 3 Figure 3: Transannular distance in a proazaphosphatrane-electrophile adduct ............................. 15 Figure 4: Crystal structure of 2-1 .................................................................................................. 16 19 1 19 19 Figure 5: F{ H} NMR and F- F EXSY NMR spectrum of a 1:1 mixture of 2-1 and B(C6F5)3 ....................................................................................................................................................... 17 Figure 6: Solid-state structure of 2-2. C: grey, N: blue, O: red, B: green, F: pink, P: orange, S: yellow, H: white ............................................................................................................................ 19 Figure 7: Solid-state structure of 2-3. C: grey, N: blue, O: red, B: green, F: pink, P: orange, S: yellow, H: white ............................................................................................................................ 20 Figure 8: Solid-state structure of 2-4. C: grey, N: blue, O: red, B: green, F: pink, P: orange, S: yellow, H: white ............................................................................................................................ 21 Figure 9: Solid-state structure of 2-5. C: grey, N: blue, O: red, B: green, F: pink, P: orange, S: yellow, H: white ...........................................................................................................................
Load more

Recommended publications
  • Hexamethylenediamine (HMDA) from Fossil Vs. Bio-Based Routes: an Economic and Life Cycle Assessment Comparative Study
    Electronic Supplementary Material (ESI) for Green Chemistry. This journal is © The Royal Society of Chemistry 2015 Hexamethylenediamine (HMDA) from Fossil vs. Bio-Based Routes: an Economic and Life Cycle Assessment Comparative Study A. B. Dros,b O. Larue,b A. Reimond,b F. De Campoa and M. Pera-Titusa* a Eco-Efficient Products and Processes Laboratory (E2P2L), UMI 3464 CNRS-Solvay, 3966 Jin Du Road, Xin Zhuang Ind. Zone, 201108 Shanghai, China. b Solvay (China) Co., Ltd., 3966 Jin Du Rd., Xin Zhuang Industrial Zone, Shanghai 201108, PR China. * Corresponding author. Tel.: +86 (0) 472445368, Fax: +86 (0) 472445399, E-mail: marc.pera-titus- [email protected] ELECTRONIC SUPPORTING INFORMATION FIGURE AND TABLE CAPTIONS Fig. S1. Speculative routes for the production of bio-based HMDA using molecules issued from biomass. Fig. S2. Flowsheet for the fossil-based route 1. Fig. S3. Flowsheet for the route Starch HFS. The bold number corresponds to the base-case value for steam consumption used in the LCA sensitivity study. The w/o HFS drying scenario value is also indicated. Fig. S4. Flowsheet for the bio-based route 2. Fig. S5. Flowsheet for the bio-based route 3. The bold numbers correspond to the base-case values used in the LCA sensitivity study. For HFS, the best- and worst case scenario values are also indicated. Fig. S6. Flowsheet for the bio-based route 4. Fig. S7. Evolution of market price of butadiene and HFCS42%. Data obtained from ref.18 and ref.21, respectively. Fig. S8. Impact score breakdown for ozone depletion (midpoint category 2) for HMDA production in France and Germany.
    [Show full text]
  • NBO Applications, 2020
    NBO Bibliography 2020 2531 publications – Revised and compiled by Ariel Andrea on Aug. 9, 2021 Aarabi, M.; Gholami, S.; Grabowski, S. J. S-H ... O and O-H ... O Hydrogen Bonds-Comparison of Dimers of Thiocarboxylic and Carboxylic Acids Chemphyschem, (21): 1653-1664 2020. 10.1002/cphc.202000131 Aarthi, K. V.; Rajagopal, H.; Muthu, S.; Jayanthi, V.; Girija, R. Quantum chemical calculations, spectroscopic investigation and molecular docking analysis of 4-chloro- N-methylpyridine-2-carboxamide Journal of Molecular Structure, (1210) 2020. 10.1016/j.molstruc.2020.128053 Abad, N.; Lgaz, H.; Atioglu, Z.; Akkurt, M.; Mague, J. T.; Ali, I. H.; Chung, I. M.; Salghi, R.; Essassi, E.; Ramli, Y. Synthesis, crystal structure, hirshfeld surface analysis, DFT computations and molecular dynamics study of 2-(benzyloxy)-3-phenylquinoxaline Journal of Molecular Structure, (1221) 2020. 10.1016/j.molstruc.2020.128727 Abbenseth, J.; Wtjen, F.; Finger, M.; Schneider, S. The Metaphosphite (PO2-) Anion as a Ligand Angewandte Chemie-International Edition, (59): 23574-23578 2020. 10.1002/anie.202011750 Abbenseth, J.; Goicoechea, J. M. Recent developments in the chemistry of non-trigonal pnictogen pincer compounds: from bonding to catalysis Chemical Science, (11): 9728-9740 2020. 10.1039/d0sc03819a Abbenseth, J.; Schneider, S. A Terminal Chlorophosphinidene Complex Zeitschrift Fur Anorganische Und Allgemeine Chemie, (646): 565-569 2020. 10.1002/zaac.202000010 Abbiche, K.; Acharjee, N.; Salah, M.; Hilali, M.; Laknifli, A.; Komiha, N.; Marakchi, K. Unveiling the mechanism and selectivity of 3+2 cycloaddition reactions of benzonitrile oxide to ethyl trans-cinnamate, ethyl crotonate and trans-2-penten-1-ol through DFT analysis Journal of Molecular Modeling, (26) 2020.
    [Show full text]
  • Refereed Publications (A = Article, C = Communication, R = Review)
    Curriculum Vitae: Douglas W. Stephan FRSC, FRS Current Address Department of Chemistry, University of Toronto, 80 St. George St. Toronto, ON, M5S3H6 [email protected]; [email protected] Phone: 416-946-3294; Cell: 647-339-3568; Admin. Asst: Shanna Pritchard 416-978-8940, [email protected] webpage: http://www.chem.utoronto.ca/staff/DSTEPHAN Home Address 47 St. Clair Ave. W., Suite 302, Toronto, ON. M4V 3A5; Home: 416-619-5901 Personal Born in Hamilton, Ontario, CANADA July 27 1953, married (Dianne L. Gunn) two adult children (David and Kathryn) Citizenship Canadian Education Ph.D 1980 (University of Western Ontario), B.Sc. 1976 (McMaster University, summa cum laude) Positions Held 2018-present University Professor, University of Toronto 2008-2018 Professor, University of Toronto 2016-2019 Chair, Editorial Board of Chemical Society Reviews 2016-2018 Einstein Visiting Fellow, TU Berlin. 2011-2017 Associate Editor, Chemical Society Reviews 2006 (Oct) International Research Guest Professor, WW-Universitaet Muenster 2008-2021 Canada Research Chair in Catalysis and New Materials (UToronto) 2005-2007 Canada Research Chair in Catalysis and New Materials (UWindsor) 2003-2006 Head, Department of Chemistry & Biochemistry 2002-2007 University Professor, University of Windsor 2002-2003 Humboldt Senior Awardee, WW-Universitaet Muenster 2001-2006 NSERC/NOVA Chemicals Corporation Industrial Research Chair 1995 DAAD Visiting Scientist, Muenster, Germany (declined) 1995 NSERC/DFG Visiting Scientist, WW-Universitaet Muenster. 1992-2002
    [Show full text]
  • Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds
    Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds Library Listing – 1,523 spectra Subset of Aldrich FT-IR Library related to organometallic, inorganic, boron and deueterium compounds. The Aldrich Material-Specific FT-IR Library collection represents a wide variety of the Aldrich Handbook of Fine Chemicals' most common chemicals divided by similar functional groups. These spectra were assembled from the Aldrich Collections of FT-IR Spectra Editions I or II, and the data has been carefully examined and processed by Thermo Fisher Scientific. Aldrich Organometallic, Inorganic, Silanes, Boranes, and Deuterated Compounds Index Compound Name Index Compound Name 1066 ((R)-(+)-2,2'- 1193 (1,2- BIS(DIPHENYLPHOSPHINO)-1,1'- BIS(DIPHENYLPHOSPHINO)ETHAN BINAPH)(1,5-CYCLOOCTADIENE) E)TUNGSTEN TETRACARBONYL, 1068 ((R)-(+)-2,2'- 97% BIS(DIPHENYLPHOSPHINO)-1,1'- 1062 (1,3- BINAPHTHYL)PALLADIUM(II) CH BIS(DIPHENYLPHOSPHINO)PROPA 1067 ((S)-(-)-2,2'- NE)DICHLORONICKEL(II) BIS(DIPHENYLPHOSPHINO)-1,1'- 598 (1,3-DIOXAN-2- BINAPH)(1,5-CYCLOOCTADIENE) YLETHYNYL)TRIMETHYLSILANE, 1140 (+)-(S)-1-((R)-2- 96% (DIPHENYLPHOSPHINO)FERROCE 1063 (1,4- NYL)ETHYL METHYL ETHER, 98 BIS(DIPHENYLPHOSPHINO)BUTAN 1146 (+)-(S)-N,N-DIMETHYL-1-((R)-1',2- E)(1,5- BIS(DI- CYCLOOCTADIENE)RHODIUM(I) PHENYLPHOSPHINO)FERROCENY TET L)E 951 (1,5-CYCLOOCTADIENE)(2,4- 1142 (+)-(S)-N,N-DIMETHYL-1-((R)-2- PENTANEDIONATO)RHODIUM(I), (DIPHENYLPHOSPHINO)FERROCE 99% NYL)ETHYLAMIN 1033 (1,5- 407 (+)-3',5'-O-(1,1,3,3- CYCLOOCTADIENE)BIS(METHYLD TETRAISOPROPYL-1,3- IPHENYLPHOSPHINE)IRIDIUM(I)
    [Show full text]
  • BUTADIENE AS a CHEMICAL RAW MATERIAL (September 1998)
    Abstract Process Economics Program Report 35D BUTADIENE AS A CHEMICAL RAW MATERIAL (September 1998) The dominant technology for producing butadiene (BD) is the cracking of naphtha to pro- duce ethylene. BD is obtained as a coproduct. As the growth of ethylene production outpaced the growth of BD demand, an oversupply of BD has been created. This situation provides the incen- tive for developing technologies with BD as the starting material. The objective of this report is to evaluate the economics of BD-based routes and to compare the economics with those of cur- rently commercial technologies. In addition, this report addresses commercial aspects of the butadiene industry such as supply/demand, BD surplus, price projections, pricing history, and BD value in nonchemical applications. We present process economics for two technologies: • Cyclodimerization of BD leading to ethylbenzene (DSM-Chiyoda) • Hydrocyanation of BD leading to caprolactam (BASF). Furthermore, we present updated economics for technologies evaluated earlier by PEP: • Cyclodimerization of BD leading to styrene (Dow) • Carboalkoxylation of BD leading to caprolactam and to adipic acid • Hydrocyanation of BD leading to hexamethylenediamine. We also present a comparison of the DSM-Chiyoda and Dow technologies for producing sty- rene. The Dow technology produces styrene directly and is limited in terms of capacity by the BD available from a world-scale naphtha cracker. The 250 million lb/yr (113,000 t/yr) capacity se- lected for the Dow technology requires the BD output of two world-scale naphtha crackers. The DSM-Chiyoda technology produces ethylbenzene. In our evaluations, we assumed a scheme whereby ethylbenzene from a 266 million lb/yr (121,000 t/yr) DSM-Chiyoda unit is combined with 798 million lb/yr (362,000 t/yr) of ethylbenzene produced by conventional alkylation of benzene with ethylene.
    [Show full text]
  • The Reactivity of Hydrogen and Carbon Dioxide Mediated by Main Group Compounds
    THE REACTIVITY OF HYDROGEN AND CARBON DIOXIDE MEDIATED BY MAIN GROUP COMPOUNDS A dissertation submitted to Imperial College London for the degree of Doctor of Philosophy By Thomas James Herrington MChem (Oxon), Imperial College London May 2014 CID: 00467189 Supervised By Dr Andrew Ashley & Dr George Britovsek Chemistry Department 1 ABSTRACT The Reactivity of Hydrogen and Carbon Dioxide Mediated by Main Group Compounds The focus of this thesis has been the design and synthesis of new frustrated Lewis pair (FLP) systems which from structural modifications retain their ability to activate H2/CO2, while displaying differing reactivity modes. Chapter Two describes the first practical synthesis of tris[3,5- bis(trifluoromethyl)phenyl]borane (BArF18). Gutmann-Beckett Lewis acidity measurements reveal that this borane is a more powerful Lewis acid than B(C6F5)3, but it nevertheless is found to bind H2O much more reversibly than B(C6F5)3. The BArF18/2,2,6,6- tetramethylpiperidine (TMP) FLP provides a rare example of H2 activation in Et2O solvent, in which the borohydride salt has been structurally characterised by X-ray crystallography. A – novel bridging borohydride [-H(BArF18)2] was revealed, which contrasts to the characteristic terminal borohydrides formed by other borane based mediated FLP systems. Chapter Three details the design of fluorinated trisalkylboranes including B[CH(C6F5)2]3 which has been synthesised for the first time. This borane has been structurally characterised using X-ray crystallography and displays hydrogen bonding interactions between the ortho fluorines on each aryl ring and the adjacent CH proton. Interestingly, and despite this borane showing no Lewis acidity using Gutmann-Beckett and Childs techniques, the B[CH(C6F5)2]3/TMP FLP provides a rare example of H2 activation in THF solvent.
    [Show full text]
  • Phosphorus Lewis Acids: Emerging Reactivity and Applications in Catalysis
    Chemical Society Reviews Phosphorus Lewis Acids: Emerging Reactivity and Applications in Catalysis Journal: Chemical Society Reviews Manuscript ID: CS-REV-06-2015-000516.R1 Article Type: Tutorial Review Date Submitted by the Author: 30-Jul-2015 Complete List of Authors: Bayne, Julia; University of Toronto, Chemistry Stephan, Douglas; University of Toronto, Department of Chemistry Page 1 of 10 ChemicalPlease do notSociety adjust Reviews margins Journal Name ARTICLE Phosphorus Lewis Acids: Emerging Reactivity and Applications in Catalysis a a* Received 00th January 20xx, J. M. Bayne and D. W. Stephan Accepted 00th January 20xx Part of the renaissance in main group chemistry has been a result of the focus on reactivity. This has led to the DOI: 10.1039/x0xx00000x development of applications in stoichiometric reactivity and catalysis. In this tutorial review, we focus attention on the role of phosphorus-based Lewis acids in such advances. While early literature recognizes the role of P(III) and P(V) www.rsc.org/ electrophiles in coordination chemistry, it has generally been more recent studies that have focused on applications of this Lewis acidity. Applications of these novel P-based Lewis acids in stoichiometric reactivity, Lewis acid catalysis and frustrated Lewis pair (FLP) reactivity are reviewed. These advances demonstrate that P-based Lewis acids are a powerful tool for further developments in metal-free catalysis. Key Learning Points 1. The development of main group catalysis has contributed to significant advancements in catalytic and stoichiometric transformations. 2. Although P(III) species are typical Lewis bases, phosphenium cations have demonstrated electron accepting abilities. 3. As saturated acceptors, phosphorus(V)-based Lewis acids derive their acidity from a low lying σ* orbital.
    [Show full text]
  • Group 16 Elements in Frustrated Lewis Pair Chemistry
    Group 16 Elements in Frustrated Lewis Pair Chemistry by Fu An Tsao A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Chemistry University of Toronto © Copyright by Fu An Tsao 2018 Group 16 Elements in Frustrated Lewis Pair Chemistry Fu An Tsao Doctor of Philosophy Department of Chemistry University of Toronto 2018 Abstract Frustrated Lewis Pairs (FLPs) describe combinations of sterically encumbered Lewis acids and bases that do not form classical adducts. This unquenched reactivity has been shown to activate a wide plethora of small molecules, including H2, CO2, alkynes and ketones. While many different main group compounds have been applied in this context, studies of group 16 elements in FLP chemistry remain scarce. The main objective of this dissertation is to expand the scope of FLP chemistry to include group 16 elements, as they can function both as Lewis bases and as Lewis acids. The first portion of this dissertation focuses on the syntheses and reactivity studies of tellurium-boron heterocycles, wherein tellurium acts as a Lewis base. 1,1-carboboration of tellurium-substituted acetylides was shown to proceed smoothly at room temperature, leading to the formation of Te/B intramolecular FLP and 1,4-telluraborine. Several 1,4- telluraborines were found to have mild to high aromaticity as manifested by their unusual stability against oxygen and moisture. They can also undergo a number of unique reactions, including FLP-type alkyne exchange reactions and selective protonolysis of the exocyclic B–C bond. These findings allowed for the facile derivatization of this new class of compounds.
    [Show full text]
  • Bifunctional Systems in the Chemistry of Frustrated Lewis Pairs
    Bifunctional Systems in the Chemistry of Frustrated Lewis Pairs by Xiaoxi Zhao A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Department of Chemistry University of Toronto © Copyright by Xiaoxi Zhao 2012 Library and Archives Bibliothèque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l'édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 978-0-494-97235-9 Our file Notre référence ISBN: 978-0-494-97235-9 NOTICE: AVIS: The author has granted a non- L'auteur a accordé une licence non exclusive exclusive license allowing Library and permettant à la Bibliothèque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l'Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans le loan, distrbute and sell theses monde, à des fins commerciales ou autres, sur worldwide, for commercial or non- support microforme, papier, électronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriété du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette thèse. Ni thesis. Neither the thesis nor la thèse ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent être imprimés ou autrement printed or otherwise reproduced reproduits sans son autorisation.
    [Show full text]
  • United States Patent (19) (11) 4,045,495 Nazarenko Et Al
    United States Patent (19) (11) 4,045,495 Nazarenko et al. (45) Aug. 30, 1977 (54) PROCESS FOR THE PRE PARATION OF TRARYLBORANES FOREIGN PATENT DOCUMENTS (75) Inventors: Nicholas Nazarenko; William Carl 583,006 9/1959 Canada Seidel, both of Orange, Tex. 814,647 6/1959 United Kingdom (73) Assignee: E. I. Du Pont de Nemours and Primary Examiner-Helen M. S. Sneed Company, Wilmington, Del. (57) ABSTRACT 21 Appl. No.: 630,995 Preparation of triarylboranes, e.g. triphenylborane by 22 Filed: Nov. 12, 1975 reacting an alkali metal, e.g. sodium; an organohalide, e.g. chlorobenzene and an orthoborate ester, e.g. triiso (51) Int. Cl’................................................ COTF 5/04 propylorthoborate in an inert organic solvent, recover 52 U.S. C. .............................................. 260/606.5 B ing the borane by contacting the reaction product with (58) Field of Search .................................. 260/606.5 B water while maintaining the ratio of borane to hydroly (56) References Cited sis products (e.g. borinic acid) at at least 13/1, distilling U.S. PATENT DOCUMENTS volatiles from the aqueous mixture and contacting the resultant material with acid to a pH not less than about 2,884,441 4/1959 Groszas ........... - - - - 260/606.5 B X 6 to form the borane. 3,030,406 4/1962 Washburn et al. ... 260/606. SB X 3,090,801 5A963 Washburn et al. ..... ... 260/606.5 B X 3, 19,857 A1964 Yates et al. ...................... 260/462 C 7 Claims, 1 Drawing Figure U.S. Patent Aug. 30, 1977 4,045,495 4,045,495 1 2 1-5 with chlorobenzene and
    [Show full text]
  • Investigations Into the Hydrogenation of Epoxides by Frustrated Lewis
    Investigations into the Frustrated Lewis Pair-Catalyzed Hydrogenation of Epoxides MASTERTHESIS Martine R. Tiddens 19-02-2016 Supervisor: Dr. Matthias Otte Organic Chemistry and Catalysis Debye Institute for Nanomaterials Science 2 Abstract Traditionally hydrogenation of unsaturated substrates is a transition metal (TM)-catalyzed or stoichiometric transformation. The report about heterolytic H2-activation via Frustrated Lewis Pairs (FLP) allows the performance of classic TM-catalyzed reactions in an organocatalytic fashion. In the last decade the substrate scope for FLP-catalyzed hydrogenation has grown steadily. However, to the best of our knowledge epoxides have not yet been successfully reduced. The epoxide motive is an important building block in organic synthesis or product in natural product synthesis. Currently, hydrogenation of epoxides to alcohols is a stoichiometric or a TM-complex catalyzed transformation. Here, attempts to FLP-catalyzed hydrogenations of epoxides to alcohols are described. The known FLPs B(C6F5)3/1,4-dioxane and B(C6F5)3/diethyl ether, which are used for the FLP-catalyzed hydrogenation of carbonyl moieties, were tested for possible hydrogenation of epoxides. Meinwald rearrangement of the epoxide to an aldehyde is observed. With this result a tandem isomerization-hydrogenation reaction was envisioned. Here an epoxide rearranges to an aldehyde, upon which it should be reduced to an alcohol. Unfortunately, this reaction was not successful. The reactivity of less electron-poor Lewis acids in FLP-catalyzed hydrogenation of epoxides was investigated. Upon investigations of adduct formation between the Lewis acids with trans- phenylpropane oxide, a Lewis acid dependent reactivity of the epoxide was found. trans-phenylpropane oxide dimerizes upon stoichiometric exposure to B(C6F5)3, but isomerizes to an aldehyde when exposed to B(C7H8)3.
    [Show full text]
  • Novel Olefin Polymerization Pre-Catalyst Bearing an Inversely- Polarized Phosphaalkene Ethenolate Monoanionic Bidentate Ligand and Its Polymerization Studies
    NOVEL OLEFIN POLYMERIZATION PRE-CATALYST BEARING AN INVERSELY- POLARIZED PHOSPHAALKENE ETHENOLATE MONOANIONIC BIDENTATE LIGAND AND ITS POLYMERIZATION STUDIES. Juan Enrique Rodriguez Villanueva A thesis submitted to the faculty graduate studies in Partial fulfillment of the requirements for the degree of Master of Science Graduate Program in Chemistry York University Toronto, Ontario SePtember 2019 © Juan Enrique Rodriguez Villanueva, 2019 Abstract The synthesis and structure elucidation of the first monoanionic bidentate ligand bearing an inversely-Polarized Phosphaalkene, its Precursors and the first titanium complex bearing such ligand are herein rePorted. Single-crystal X-ray studies of the titanium complex confirmed the coordination of the bidentate ligand using the Phosphaalkene Phosphorus and ethenolate oxygen atoms with a strong evidence that there is charge delocalization through the metallocycle and the imidazole ring. The thermal stability of the Phosphaalkene–ethenolate ligand and the titanium complex at high temperature is rePorted. The new titanium complex displayed an activity for ethylene Polymerization up to 9.2 kg PE mol cat–1 h–1. The polyethylene Produced was linear with –1 a low degree of branching, an average molecular weight of ~ 6000 g mol and a Tm of 130.0 °C. II Dedication Esta tesis es dedicada con mucho cariño a mi familia, pero en especial a mi mamá por todo el amor y apoyo que me ha brindado durante todos mis estudios. – Por eso y más Muchas Gracias. III Acknowledgements I would like to thank Professor Gino G. Lavoie for the guidance, Patience and suPPort throughout my MSc. degree. I would like to thank Professors Pierre Potvin, Arturo Orellana, and Bridget Stutchbury for being Part of my suPervisory and/ or examination committee.
    [Show full text]