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Non-Traditional Hydrogen Bond Explanation of Asymmetric Catalysis of Mukaiyama Aldol Reactions by Dinuclear Zinc Semi- Crown Ligands
Duquesne University Duquesne Scholarship Collection Undergraduate Research and Scholarship Symposium 2016-04-06 Non-traditional hydrogen bond explanation of asymmetric catalysis of Mukaiyama aldol reactions by dinuclear zinc semi- crown ligands Ayan N. Ahmed Duquesne University Brandon Vernier Duquesne University Jeffrey Rohde Franciscan University of Steubenville Jeffrey D. Evanseck Duquesne University Follow this and additional works at: https://dsc.duq.edu/urss Part of the Chemistry Commons Non-traditional hydrogen bond explanation of asymmetric catalysis of Mukaiyama aldol reactions by dinuclear zinc semi-crown ligands. (2016). Retrieved from https://dsc.duq.edu/urss/2016/proceedings/2 This Paper is brought to you for free and open access by Duquesne Scholarship Collection. It has been accepted for inclusion in Undergraduate Research and Scholarship Symposium by an authorized administrator of Duquesne Scholarship Collection. Non-traditional hydrogen bond explanation of asymmetric catalysis of Mukaiyama aldol reactions by dinuclear zinc semi-crown ligands Ayan N. Ahmed, Brandon Vernier, Jeffrey Rohde, and Jeffrey D. Evanseck Bayer School of Natural and Environmental Sciences Faculty Advisor: Jeffrey Evanseck, Ph.D. Introduction The Pollution Prevention Act of 1990 put green chemistry at the forefront of chemical design and synthesis to ensure the sanctity and sustainability of the environment.1 Yet, a majority of catalysts employed today are metal based and continue to be dangerously toxic. Consequently, the dream of green chemistry is far from reaching its full potential. Our work on metal free catalysis is to first understand the mechanistic and electronic control of metals in catalysis. The foundation of our work has been possible through combining the advances of two renown scientists: E. -
Organic Chemistry
Wisebridge Learning Systems Organic Chemistry Reaction Mechanisms Pocket-Book WLS www.wisebridgelearning.com © 2006 J S Wetzel LEARNING STRATEGIES CONTENTS ● The key to building intuition is to develop the habit ALKANES of asking how each particular mechanism reflects Thermal Cracking - Pyrolysis . 1 general principles. Look for the concepts behind Combustion . 1 the chemistry to make organic chemistry more co- Free Radical Halogenation. 2 herent and rewarding. ALKENES Electrophilic Addition of HX to Alkenes . 3 ● Acid Catalyzed Hydration of Alkenes . 4 Exothermic reactions tend to follow pathways Electrophilic Addition of Halogens to Alkenes . 5 where like charges can separate or where un- Halohydrin Formation . 6 like charges can come together. When reading Free Radical Addition of HX to Alkenes . 7 organic chemistry mechanisms, keep the elec- Catalytic Hydrogenation of Alkenes. 8 tronegativities of the elements and their valence Oxidation of Alkenes to Vicinal Diols. 9 electron configurations always in your mind. Try Oxidative Cleavage of Alkenes . 10 to nterpret electron movement in terms of energy Ozonolysis of Alkenes . 10 Allylic Halogenation . 11 to make the reactions easier to understand and Oxymercuration-Demercuration . 13 remember. Hydroboration of Alkenes . 14 ALKYNES ● For MCAT preparation, pay special attention to Electrophilic Addition of HX to Alkynes . 15 Hydration of Alkynes. 15 reactions where the product hinges on regio- Free Radical Addition of HX to Alkynes . 16 and stereo-selectivity and reactions involving Electrophilic Halogenation of Alkynes. 16 resonant intermediates, which are special favor- Hydroboration of Alkynes . 17 ites of the test-writers. Catalytic Hydrogenation of Alkynes. 17 Reduction of Alkynes with Alkali Metal/Ammonia . 18 Formation and Use of Acetylide Anion Nucleophiles . -
Aldehydes and Ketones
12 Aldehydes and Ketones Ethanol from alcoholic beverages is first metabolized to acetaldehyde before being broken down further in the body. The reactivity of the carbonyl group of acetaldehyde allows it to bind to proteins in the body, the products of which lead to tissue damage and organ disease. Inset: A model of acetaldehyde. (Novastock/ Stock Connection/Glow Images) KEY QUESTIONS 12.1 What Are Aldehydes and Ketones? 12.8 What Is Keto–Enol Tautomerism? 12.2 How Are Aldehydes and Ketones Named? 12.9 How Are Aldehydes and Ketones Oxidized? 12.3 What Are the Physical Properties of Aldehydes 12.10 How Are Aldehydes and Ketones Reduced? and Ketones? 12.4 What Is the Most Common Reaction Theme of HOW TO Aldehydes and Ketones? 12.1 How to Predict the Product of a Grignard Reaction 12.5 What Are Grignard Reagents, and How Do They 12.2 How to Determine the Reactants Used to React with Aldehydes and Ketones? Synthesize a Hemiacetal or Acetal 12.6 What Are Hemiacetals and Acetals? 12.7 How Do Aldehydes and Ketones React with CHEMICAL CONNECTIONS Ammonia and Amines? 12A A Green Synthesis of Adipic Acid IN THIS AND several of the following chapters, we study the physical and chemical properties of compounds containing the carbonyl group, C O. Because this group is the functional group of aldehydes, ketones, and carboxylic acids and their derivatives, it is one of the most important functional groups in organic chemistry and in the chemistry of biological systems. The chemical properties of the carbonyl group are straightforward, and an understanding of its characteristic reaction themes leads very quickly to an understanding of a wide variety of organic reactions. -
The Nakanishi Symposium on Natural Products & Bioorganic Chemistry
The Nakanishi Symposium on Natural Products & Bioorganic Chemistry March 19, 2021 Sponsored by The Chemical Society of Japan & The American Chemical Society ー1ー Yoshito Kishi Professor Emeritus, Harvard University ■EDUCATION Bachelor of Science, Nagoya University 1961 Doctor of Philosophy (Chemistry), Nagoya University (Professors Yoshimasa Hirata and Toshio Goto) 1966 Postdoctoral Research Fellow (Chemistry), Harvard University (Professor R. B. Woodward) 1966-1968 ■ACADEMIC APPOINTMENT Instructor of Chemistry, Nagoya University 1966-1970 Associate Professor of Agricultural Chemistry, Nagoya University 1970-1974 Visiting Professor of Chemistry, Harvard University 1972-1973 Professor of Chemistry, Harvard University 1974-1982 Morris Loeb Professor of Chemistry, Harvard University 1982-2002 Morris Loeb Professor of Chemistry, Emeritus, Harvard University 2002- ー2ー ■RESEARCH TOPICS (chronological order) 1. Chemical studies of bioluminescence: The luminescent substance named luciferin is an unstable compound, making its structural determination extremely difficult. Dr. Kishi, however, determined the structures of luciferins, such as those in Cypridina, Genji fireflies, krill, dinoflagellates, and the luminous shellfish of Latia (1960s–1980s). 2. Total synthesis of complex natural products: The pufferfish toxin tetrodotoxin, the structure of which was determined in 1964, is still known as one of the most difficult natural products to synthesize due to its highly functionalized structural complexity. Dr. Kishi achieved the world’s first total synthesis of this compound in 1972. Later, he achieved total synthesis of the paralytic shellfish toxin saxitoxin, the anticancer drug mitomycin C, the fungus toxin sporidesmin, and the β-lactam antibiotics (1970s–1980s). 3. Development of acyclic stereocontrol in total synthesis of natural products: Until the early 1970s, total synthesis of polyether antibiotics was almost impossible due to the presence of numerous asymmetric centers. -
Direct Visualization of a Mechanochemically Induced Molecular Rearrangement Karen J
Angewandte Communications Chemie How to cite: Angew. Chem. Int. Ed. 2020, 59, 13458–13462 Mechanochemical Synthesis International Edition: doi.org/10.1002/anie.201914921 German Edition: doi.org/10.1002/ange.201914921 Direct Visualization of a Mechanochemically Induced Molecular Rearrangement Karen J. Ardila-Fierro, Stipe Lukin, Martin Etter, Krunoslav Uzˇarevic´, Ivan Halasz, Carsten Bolm, and JosØ G. Hernµndez* Abstract: Recent progress in the field of mechanochemistry (thio)acylations[5]). In this context, we became curious as to has expanded the discovery of mechanically induced chemical whether a combination of in situ real-time monitoring by transformations to several areas of science. However, a general synchrotron powder X-ray diffraction (PXRD), Raman fundamental understanding of how mechanochemical reac- spectroscopy, and temperature sensing could be applied for tions by ball milling occur has remained unreached. For this, the investigation of a fundamentally different type of organic we have now implemented in situ monitoring of a mechano- reaction; namely, a molecular rearrangement. As the first chemically induced molecular rearrangement by synchrotron example, we considered the emblematic benzil–benzilic acid X-ray powder diffraction, Raman spectroscopy, and real-time rearrangement in the presence of hydroxide ions (Sche- temperature sensing. The results of this study demonstrate that me 1a). molecular rearrangements can be accomplished in the solid state by ball milling and how in situ monitoring techniques enable the visualization of changes occurring at the exact instant of a molecular migration. The mechanochemical benzil–benzilic acid rearrangement is the focal point of the study. In mechanochemical reactions by ball milling, collisions of accelerated balls inside a milling container maintain a con- stant mixing of the reactants while simultaneously trans- ducing the energy required to induce specific physicochemical changes into the milled system. -
Survey, Emission and Evaluation of Volatile Organic Chemic…
Survey of chemical compounds in consumer products Survey no. 36 – 2003 Survey, emission and evaluation of volatile organic chemicals in printed matter Ole Christian Hansen and Torben Eggert Danish Technological Institute 2 Contents PREFACE 5 SUMMARY AND CONCLUSIONS 7 ABBREVIATIONS 11 1 INTRODUCTION 13 2 PRINTED MATTER 15 2.1 CONSUMPTION 15 2.2 NUMBER OF ENTERPRISES 16 2.3 PRINTING 16 2.3.1 Printing techniques 16 2.4 PAPER 17 2.5 PRINTING INKS 17 2.5.1 Solvents 18 2.5.2 Binders 19 2.5.3 Wetting agent 19 2.5.4 UV-curing inks 19 2.6 EMISSIONS DURING PRINTING 20 2.7 PRINTED MATTER IN THE HOUSEHOLD 20 2.8 DISPOSAL 21 2.9 RECYCLING 22 3 EXPOSURE 23 3.1 EMISSION MEASURING METHODS 23 3.1.1 Sampling and analyses 23 3.1.2 Screening of volatiles 23 3.1.3 Quantitative measurements 24 3.1.4 Results 25 4 EXPOSURE AND HEALTH EVALUATION 33 4.1 EXPOSURE SCENARIOS 34 4.1.1 Method 34 4.1.2 Scenarios 34 4.2 ASSESSMENT METHOD 35 4.2.1 Assessment method 35 4.2.2 Procedure for assessments 37 5 EVALUATION OF INDIVIDUAL COMPOUNDS 39 5.1 ALDEHYDES 39 5.1.1 Propanal 39 5.1.2 Pentanal 41 5.1.3 Hexanal 42 5.1.4 Heptanal 43 5.2 ALCOHOLS 44 5.2.1 2-Ethyl-1-hexanol 45 5.3 KETONES 46 5.3.1 Heptanone 46 3 5.4 ESTERS 48 5.4.1 Propanoic acid, butylester 48 5.5 FURAN 49 5.5.1 2-Pentylfuran 49 5.6 AROMATIC HYDROCARBONS 50 5.6.1 Toluene 50 5.6.2 Xylenes 53 5.6.3 Ethylbenzene 56 5.7 TERPENES 58 5.7.1 alpha-Pinene 58 5.7.2 Camphene 60 5.7.3 Limonene 61 5.7.4 Tetramethyl methenoazulene 63 5.8 ALIPHATIC HYDROCARBONS 64 6 EVALUATION OF PRINTED MATTER 68 6.1 HEALTH ASSESSMENT OF SELECTED PRINTED MATTER 68 6.1.1 Printed matter no. -
Amino Acid Catalyzed Direct Asymmetric Aldol Reactions: a Bioorganic Approach to Catalytic Asymmetric Carbon-Carbon Bond-Forming Reactions
5260 J. Am. Chem. Soc. 2001, 123, 5260-5267 Amino Acid Catalyzed Direct Asymmetric Aldol Reactions: A Bioorganic Approach to Catalytic Asymmetric Carbon-Carbon Bond-Forming Reactions Kandasamy Sakthivel, Wolfgang Notz, Tommy Bui, and Carlos F. Barbas III* Contribution from The Skaggs Institute for Chemical Biology and the Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037 ReceiVed January 3, 2001 Abstract: Direct asymmetric catalytic aldol reactions have been successfully performed using aldehydes and unmodified ketones together with commercially available chiral cyclic secondary amines as catalysts. Structure- based catalyst screening identified L-proline and 5,5-dimethyl thiazolidinium-4-carboxylate (DMTC) as the most powerful amino acid catalysts for the reaction of both acyclic and cyclic ketones as aldol donors with aromatic and aliphatic aldehydes to afford the corresponding aldol products with high regio-, diastereo-, and enantioselectivities. Reactions employing hydroxyacetone as an aldol donor provide anti-1,2-diols as the major product with ee values up to >99%. The reactions are assumed to proceed via a metal-free Zimmerman- Traxler-type transition state and involve an enamine intermediate. The observed stereochemistry of the products is in accordance with the proposed transition state. Further supporting evidence is provided by the lack of nonlinear effects. The reactions tolerate a small amount of water (<4 vol %), do not require inert reaction conditions and preformed enolate equivalents, and can be conveniently performed at room temperature in various solvents. In addition, reaction conditions that facilitate catalyst recovery as well as immobilization are described. Finally, mechanistically related addition reactions such as ketone additions to imines (Mannich- type reactions) and to nitro-olefins and R,â-unsaturated diesters (Michael-type reactions) have also been developed. -
SILP Catalysis in Gas-Phase Hydroformylation and Carbonylation A
DGMK/SCI-Conference ..Synthesis Gas Chemistry", October 4-6, 2006, Dresden, Germany SILP Catalysis in Gas-Phase Hydroformylation and Carbonylation A. Riisager*, R. Fehrmann*, M. Haumann**, P. Wasserscheid** * Department of Chemistry, Technical University of Denmark, B 207, DK-2800 Kgs. Lyngby, Denmark, ** Lehrstuhl furChemische Reaktionstechnik, Universitat Erlangen-Nurnberg, Egerlandstr. 3, D-91058, Germany Abstract Supported ionic liquid phase (SILP) catalysts are new materials consisting of an ionic liquid- metal catalyst solution highly dispersed on a porous support. The use of a non-volatile, ionic liquid catalyst phase in SILP catalysts results in a stable heterogeneous-type material with selectivity and efficiency like homogeneous catalysts. The silica-supported SILP Rh- bisphosphine hydroformylation catalyst exhibited good activities and excellent selectivities in gas phase hydroformylation with stability exceeding 700 hours time-on-stream. Spectroscopic and kinetic data confirmed the homogeneous nature of the catalyst. In the Rh- SILP catalysed carbonylation of methanol the formation of undesired by-products could be suppressed by variation of residence time and gas pressure. Introduction The immobilisation of homogeneous catalysts by ionic liquids has been studied extensively in the last decade. The ionic nature, very low volatility and thermal stability of ionic liquids make them highly suitable for biphasic ionic liquid-organic liquid transition metal catalysis.[1] The almost unlimited combinations of cation and anion allow -
A Facile Solvent-Free Cannizzaro Reaction. an Instructional Model for Introductory Organic Chemistry Laboratory
In the Laboratory edited by Green Chemistry Mary M. Kirchhoff ACS Education Division Washington, DC 20036 A Facile Solvent-Free Cannizzaro Reaction An Instructional Model for Introductory Organic Chemistry Laboratory Sonthi Phonchaiya and Bhinyo Panijpan Institute for Innovation and Development of Learning Process, Mahidol University, Bangkok 10400, Thailand Shuleewan Rajviroongit* Department of Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; *[email protected] Tony Wright School of Education, University of Queensland, 4072, QLD, Australia Joanne T. Blanchfield School of Molecular and Microbial Sciences, University of Queensland, 4072, QLD, Australia To make students in chemistry laboratory more apprecia- 2-chlorobenzyl alcohol by filtration: the solid 2-chlorobenzyl tive of the environmental aspects of chemistry, it is important alcohol retained by the filter was washed twice with water. After that the laboratory exercise address possible environmental im- acidification of potassium 2-chlorobenzoate and filtration, the pacts, for example, energy used, chemical wastes produced, and precipitated 2-chlorobenzoic acid was also rinsed with water. In the use of organic solvents. A reaction that involves only a small both cases small amounts of products were sacrificed, leading to amount(s) of reactants in an aqueous solvent with no organic slightly reduced yields. The reaction is shown in Scheme I. solvent used in the product purification step would result in a Students achieved yields of 35–85% for each pure product. greener chemistry laboratory. A pedagogical method such as They characterized their partially dried products by comparing guided inquiry will make the laboratory more learner-centered the Rf values on TLC with the authentic samples. -
Accuracy and Methodologic Challenges of Volatile Organic Compound–Based Exhaled Breath Tests for Cancer Diagnosis: a Systematic Review and Pooled Analysis
1 Supplementary Online Content Hanna GB, Boshier PR, Markar SR, Romano A. Accuracy and Methodologic Challenges of Volatile Organic Compound–Based Exhaled Breath Tests for Cancer Diagnosis: A Systematic Review and Pooled Analysis. JAMA Oncol. Published online August 16, 2018. doi:10.1001/jamaoncol.2018.2815 Supplement. eTable 1. Search strategy for cancer systematic review eTable 2. Modification of QUADAS-2 assessment tools eTable 3. QUADAS-2 results eTable 6. STARD assessment of each study eTable 7. Summary of factors reported to influence levels of volatile organic compounds within exhaled breath eFigure 1. Risk of bias and applicability concerns using QUADAS-2 eFigure 2. PRISMA flowchart of literature search eTable 4. Details of studies on exhaled volatile organic compounds in cancer eTable 5. Cancer VOCs in exhaled breath and their chemical class. eFigure 3. Chemical classes of VOCs reported in different tumor sites. This supplementary material has been provided by the authors to give readers additional information about their work. © 2018 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 10/01/2021 2 eTable 1. Search strategy for cancer systematic review # Search 1 (cancer or neoplasm* or malignancy).ab. 2 limit 1 to abstracts 3 limit 2 to cochrane library [Limit not valid in Ovid MEDLINE(R),Ovid MEDLINE(R) Daily Update,Ovid MEDLINE(R) In-Process,Ovid MEDLINE(R) Publisher; records were retained] 4 limit 3 to english language 5 limit 4 to human 6 limit 5 to yr="2000 -Current" 7 limit 6 to humans 8 (cancer or neoplasm* or malignancy).ti. 9 limit 8 to abstracts 10 limit 9 to cochrane library [Limit not valid in Ovid MEDLINE(R),Ovid MEDLINE(R) Daily Update,Ovid MEDLINE(R) In-Process,Ovid MEDLINE(R) Publisher; records were retained] 11 limit 10 to english language 12 limit 11 to human 13 limit 12 to yr="2000 -Current" 14 limit 13 to humans 15 7 or 14 16 (volatile organic compound* or VOC* or Breath or Exhaled).ab. -
Nomination Background: N-Pentanal (CASRN: 110-62-3)
SUMMARY OF DATA FOR CHEMICAL SELECTION n-VALERALDEHYDE CAS NO. 110-62-3 BASIS OF NOMINATION TO THE CSWG The nomination of valeraldehyde to the CSWG is based on high production volume, exposure potential, and suspicion of carcinogenicity. Dr. Elizabeth Weisburger, a member of the American Conference of Governmental Industrial Hygienists (ACGIH) TLV Committee as well as the Chemical Selection Working Group (CSWG), provided a list of 281 chemical substances with ACGIH recommended TLVs for which there were no long term studies cited in the supporting data and no designations with respect to carcinogenicity. She presented the list to the Chemical Selection Planning Group (CSPG) for evaluation as chemicals which may warrant chronic testing: it was affirmed at the CSPG meeting held on August 9, 1994, that the 281 "TLV Chemicals" be reviewed as a Class Study. As a result of the class study review, valeraldehyde is presented as a candidate for testing by the National Toxicology Program because of: •potential for occupational exposures based on high production volume (25-100 million lbs) and estimate of worker exposure •evidence of occupational exposures based on TLV and other literature documentation •universal potential for general population exposures based on endogenous and exogenous occurrence in many consumed products and in environmental media •suspicion of carcinogenicity based on short-term test results and aldehyde structure •lack of chronic toxicity data. SELECTION STATUS ACTION BY CSWG : 9/25/96 Studies requested : - Subchronic (90-day) - Mouse lymphoma (to be performed in the NCI Short-Term Test Program (STTP)) Priority : Moderate Rationale/Remarks : - Potential for widespread human exposure - Suspicion of carcinogenicity INPUT FROM GOVER NMENT AGENCIES/INDUSTRY Dr. -
Profiles, Pathways and Dreams: from Naïveté to the Hist Award
Bull. Hist. Chem., VOLUME 43, Number 2 (2018) 45 PROFILES, PATHWAYS AND DREAMS: FROM NAÏVETÉ TO THE HIST AWARD Jeffrey I. Seeman, Department of Chemistry, University of Richmond, Richmond, VA, USA, 23173, [email protected] Editor’s Note the Bulletin for the History of Chemistry publishes that presentation. Seeman, a strong supporter of the Bulletin, Jeffrey I. Seeman of the University of Richmond preferred to be in the audience rather than lecture at the is the 2017 recipient of the HIST Award for Outstand- symposium. Nonetheless, he happily provided an award ing Lifetime Achievement in the History of Chemistry, manuscript for the Bulletin. He consulted several col- awarded annually by the American Chemical Society leagues on an appropriate topic for his award paper, and (ACS) Division of the History of Chemistry (HIST). This the following article is the result. In what follows, readers international award has been granted since 1956 under will get to know several of the 20th century’s prominent sequential sponsorships by the Dexter Chemical Com- organic chemists as well as Seeman. pany, the Sidney M. Edelstein Family and the Chemical Heritage Foundation, and HIST. Among the highlights —Carmen Giunta, Editor of Seeman’s work in history of chemistry are numerous articles on the history of 20th-century organic chemistry, Introduction service on the executive committee of HIST including a term as chair, founding and administering HIST’s Cita- Work like you don’t need the money. Love like tion for Chemical Breakthrough Award program, the pro- you’ve never been hurt. Dance like nobody’s watching.