Day 2 :
Keynote Forum
Evgenii S Stoyanov
Novosibirsk State University, Russia
Keynote: Carbocations in condensed phases: Stabilization via hyperconjugation, polarization, and hydrogen bonding
Time : 09:30 AM
Biography:
Evgenii S Stoyanov received a PhD degree from Vernadsky Institute of Geochemistry & Analytical Chemistry (Academy of Sciences of USSR), Moscow, Russia, and the Doctor of Science degree in Chemistry in 1991 from Mendeleyev University of Chemical Technology, Russia. He has published 139 papers in reputable journals.
Abstract:
A unified concept of the carbocations stabilization in gas, liquid, and solid phases is proposed. For the tert-butyl cation (t-Bu+), which is an iconic example of carbocations, the empirical gas-phase infrared (IR) spectrum shares only a deceptive similarity with the spectrum predicted by theory (for optimized t-Bu+ structure). They have important but so far unnoticed differences. At the same time, the IR spectra of t-Bu+ show a strong similarity to gas and condensed phases, thereby confirming that the nature of intramolecular stabilization of carbocations does not depend on the phase state. The IR spectroscopic analysis of the hydrogen bonding of t-Bu+ with the environment, together with X-ray crystallographic data, reveals that one CH3 group of t-Bu+ differs from the two others. It is presumably polarized and less involved in hyperconjugation in comparison with the other CH3 groups, which are strongly hyperconjugated. The pattern of changes in the IR spectra of carbocations in their salts with the least basic anion (fluorinated carborane CHB11F11ï€) in the series CH3+, C2H5+, i-C3H7+, cyclo-C4H7+, cyclo-C5H9+, methylcyclopentyl+, tert-butyl+, 2-methylbutyl+ and 2,3-dimethylbutyl+, together with the available X-ray crystallographic data, shows that the current understanding of the intramolecular stabilization of carbocations, which is based on the modern ab initio computations contradicts a number of empirical facts. In the report, these contradictions are discussed and an explanation for all the empirical data is offered. Nonetheless, this explanation does not resolve the existing discrepancies with the calculations.
Keynote Forum
Jwo Huei Jou
National Tsing Hua University, Taiwan
Keynote: Blue hazard free candlelight organic light emitting diode
Time : 10:00
Biography:
Jwo-Huei Jou received his PhD in 1986 from University of Michigan, Ann Arbor, Michigan, USA, and worked as a Postdoctoral visiting scientist at IBM-AlmadenrnResearch Center, CA, USA, till 1988 before becoming a faculty in NTHU. He chaired the department from 2006 to 2009. He has published more than 120 journalrnpapers and filed and/or been issued more than 60 patents, and has been serving as an editor of Fluorescent Materials and else.
Abstract:
Candlelight, an Organic Light-Emitting Diode (OLED) will soon become the mainstream lighting due to its numberless disruptive characteristics especially, blue hazard free lighting. This blue hazard free candlelight OLED will disrupt most of the lighting market for being safe, high quality, energy saving, and cost effective. The relatively low color temperature, e.g. 1,900 K, makes it at least 10 times safer in retina protection and 5 times better in melatonin generation as comparing with the 5,000K, bluelight-enriched white CFL, LED, and OLED counterparts. With a joint effort with Wisechip, a passive matrix OLED manufacturer showed the first demo blue hazard free, candlelight OLED street lamp which was installed in Smangus, an arboriginal tribe in Taiwan. These customer affordable luminaries will be made commercially available by the end of 2017. Light Renaissance can hence, be expected with this good light which is friendly to human eyes, physiology, artifacts, ecosystems and environment.
- Biochemistry, Polymer Chemistry, Materials Chemistry | Modern Organic Chemistry and Applications | Physical Organic Chemistry
Location: Flemingo 1&2
Chair
Gregory A Weiss
University of California, USA
Co-Chair
John A Soderquist
University of Puerto Rico, USA
Session Introduction
Jovica Badjic
The Ohio State University, USA
Title: Molecular encapsulation and ractivity with assembled baskets in water
Time : 10:40-11:00
Biography:
Jovica Badjic completed his PhD in 2001 in the area of Organic Chemistry and Post-doctoral studies from UCLA in 2003. He is currently Professor of Chemistry at the Ohio State University. He has published in the area of supramolecular chemistry and catalysis.
Abstract:
The entrapment of guest compounds with artificial hosts allows for controlling local environment and properties of a variety of analytes. In particular, one can use molecular encapsulation for stabilizing reactive intermediates, promoting chemical reactions and modulating conformational dynamics of guests. We recently developed so-called gated molecular baskets for regulating the activation energy (ï„G‡in/out) characterizing the ingress/egress of molecules and thereby chemical reactivity. Interestingly, molecular baskets were additionally found to assemble into stimuli-responsive vesicles in an aqueous environment. These nanostructured materials are capable of trapping nerve agents in water in an allosteric manner. The lecture will focus on presenting our recent efforts toward understanding working mechanisms baskets in controlling the recognition of various guests. I will also discuss the utility of assembled baskets for Cï€H activation of small hydrocarbons in water.
Kohei Torikai
Kyushu University, Japan
Title: 2-Naphthylmethoxymethyl: A Mildly Introducible and Oxidatively Removable Benzyloxymethyl-Type Protecting Group
Time : 11:20-11:40
Biography:
Kohei Torikai has completed his PhD in Osaka University (Prof. Michio Murata) and Post-doctoral studies in Osaka University (Prof. Tohru Oishi) and the University of Tokyo (Prof. Hiroaki Suga). In 2010, he started his academic career at University of Shizuoka as a Research Assistant Professor, and in the same year, moved to Kyushu University as a tenured Assistant Professor. He has published more than 20 papers, received more than 10 awards and grants, and serving as an Editorial Board Member of JSM Chemistry. His research interests are on synthetic organic, natural products, bioorganic, and medicinal chemistry.
Abstract:
Protective groups are still playing important roles in the synthesis of complex molecules, despite the recent negative campaign against using them that increase the E-factor and the number of steps. To expand the variety of protective groups, naphthylmethoxymethyl (NAPOM) was newly developed for the protection of hydroxy (including phenolic hydroxy and carboxy) and mercapto groups. The NAPOM group can be introduced in extremely mild conditions (NAPOMCl, 2,6-lutidine, rt) without concomitant acyl migration in a 1,2-diol system. Furthermore, selective removal of NAPOM in the presence of naphthylmethyl (NAP) and p-methoxybenzyl (PMB), and conversely, that of PMB in the presence of NAPOM, were realized. These results, as well as its easy handling and compatibility with various solvents, show that NAPOM is a novel and useful choice of protective groups.
Gregory A Weiss
University of California, USA
Title: Multi-step enzymatic and organic synthesis with continuous fl ow, thin fi lm fluidics
Time : 11:40-12:00
Biography:
Gregory A Weiss has earned his undergraduate and graduate degrees from the University of California, Berkeley and Harvard, respectively. He was awarded a Ruth Kirschstein National Research Service Award from the NIH, and then he pursued his Post-doctoral studies at Genentech. In the year 2000, he joined the faculty at the University of California, Irvine. He was named a Fellow of the AAAS in 2013; has also been awarded an Ig Nobel Prize in Chemistry for leading the team that unboilied an egg. His laboratory focuses on bioelectronics, single molecule enzymology, membrane proteins, continuous flow protein folding and biocatalysts
Abstract:
Inspired by the multi-step pathways used by organisms to synthesize complex natural products, we have developed thin film microfluidics for iterative chemical transformations generated by a vortex fluidic device; in these micron-scales thin films can drive protein folding and also accelerate catalysis by enzymes. To demonstrate the protein folding capabilities, we rapidly folded recombinant and naturally occurring proteins, including lysozyme from hard-boiled egg whites. Similarly, applying a vortex fluidic device can drive biocatalysis in different soluble enzymes with accelerations up to 15-fold. The thin films avoid clogging, and allow continuous feeding of simple starting materials. Flow chemistry can enable multi-step transformations with compartmentalization of each reaction before the increasingly complex intermediate flows to the next reaction site. Such control is typically not possible using conventional flasks. Assembly line synthesis can allow unprecedented reaction flexibility and processing efficiency. Examples of thin film-based continuous flow synthesis to be presented include both conventional and biosynthesis.
Morgan Stefik
University of South Carolina, USA
Title: Design of novel block co-polymers for solution processing of advanced nanomaterials
Time : 12:00-12:20
Biography:
Morgan Stefik obtained his degree in Materials Engineering from Cal Poly SLO, USA in the year 2005. He has completed his Doctoral studies in Materials Science at Cornell University under the supervision of Prof. U Wiesner and Prof. F J DiSalvo in the year 2010. After two years of Post-doctoral research at Ecole Polytechnique Federale de Lausanne with Prof. M Gratzel, he joined the University of South Carolina in the year 2013 as an Assistant Professor in the Department of Chemistry and Biochemistry. He is the Founding Director of the NSF which supported South Carolina SAXS Collaborative. His research focuses on nano- materials chemistry with emphasis on self-assembly techniques and atomic layer deposition.
Abstract:
The ability to tune nanoscale features in traditional materials can enable new properties or enhanced performance in technologies ranging from optoelectronics to super-capacitors and solar devices. Our lab takes inspiration from the promise of nanomaterials chemistry to advance the capabilities of devices for both energy conversion and storage. One of our core strategies is the design of novel block copolymer self-assembly systems that enable new levels of precision. In this talk, I will focus on recent developments where new amphiphilic block copolymers are synthesized by controlled radical techniques to enable advanced solution processing of inorganic nanostructures. Solution processing is highly scalable, but more subtly is also highly tunable to result in markedly different nanostructures. With one example, we apply thermodynamic concepts to direct the entrapment of block copolymer micelles for self-assembly with precision control. The resulting tunable isomorphic architectures have widespread applications to advance (photo) electrochemical devices.
John A Soderquist
University of Puerto Rico, USA
Title: Asymmetric organoborane conversions via the amazing 9 borabicyclo [3.3.2]decanes
Time : 12:20-12:40
Biography:
John A Soderquist completed his PhD in 1977 from the University of Colorado under the direction of Alfred Hassner. From 1977-79, he was a Post-doctoral scholar under the direction of Nobel Laureate, Herbert C Brown at Purdue University. His independent research career began at the University of San Francisco in 1979, where he became Associate Professor and Department Chairman before moving to the University of Puerto Rico in 1983. Since 1988, he has been a Full Professor of Chemistry, publishing nearly 140 articles, contributing over 400 research presentations to scientific meetings and universities world-wide and directing the thesis studies of nearly 30 PhD students. He has served as a technical consultant for several chemical and pharmaceutical companies.
Abstract:
The stereoselective addition of reagents containing the chiral 10-substituted-9-borabicyclo[3.3.2] decane (BBD) moiety to aldehydes, ketones, aldimines and ketimines will be described. The rigid and robust nature of these systems permits a wide variety of organoborane conversions to not only be conducted in a highly enantioselective manner, but also, it facilitates the recovery of the chiral borane by-product which can be recycled through simple operations. Moreover, numerous chemical conversions can be performed on these organoboranes providing remarkable new reagents for organic synthesis. The origin of the observed selectivities will be presented and discussed in terms of the compact chiral reaction centers provided by the BBD systems.
Shunying Liu
East China Normal University, China
Title: Enantioselective trapping of oxonium ylide with n-benzhydryl-α-imino ester: A rapid access to synthesis of β-tetrasubstituted α-amino acids
Biography:
Shunying Liu has completed her PhD from Wuhan University and Post-doctoral studies from Hong Kong Baptist University and Oxford University. Her research interest is mainly on asymmetric catalysis for multi-component reaction. She has published more than 50 papers in reputed journals.
Abstract:
β-Alkoxy Cβ-tetrasubstituted α-amino acid derivatives are commonly serviceable structural motifs in biologically active natural products and pharmaceuticals. Several efficient methods have been established to construct β-tetrasubstituted α-amino acids. Nevertheless, a rapid access to construction of these complex molecules from simple starting materials under mild conditions are urgently in demand. Multi-component reactions (MCRs) have provided such an approach to realize this goal. Here, a synergistic rhodium(II)/phosphoric acid catalyzed three component reaction of 3-diazooxindoles, alcohols and N-benzhydryl-α-imino ester is successfully developed to provide an efficient strategy for the rapid construction of chiral β-alkoxy Cβ-tetrasubstituted α-amino acid derivatives with high diastereoselectivity (up to 20:1 dr) and excellent enantioselectivity (up to 98:2 er) from simple starting points under mild conditions (Scheme 1). The resulting multi-component products 4 readily afforded 3-spirocyclic oxindole 5 under the standard hydrogenation conditions followed a cyclization with CSCl2 in a good yield remaining excellent enantioselectivity.
Jozef Stec
Marshall B. Ketchum University, USA
Title: Transition metal-assisted total synthesis of natural products
Time : 13:00-13:20
Biography:
Jozef Stec is currently an Associate Professor of Medicinal Chemistry at Marshall B. Ketchum University College of Pharmacy. He obtained MSc (Honors) in Molecular and Pharmaceutical Biotechnology (Gdansk University of Technology); PhD in Organic and Organometallic Chemistry (University of Southampton), and Post-doctoral training in Synthetic Medicinal Chemistry (University of Illinois at Chicago). His research interest is in the area of widely understood synthetic organic and modern medicinal chemistry. His research productivity is documented by manuscripts published in reputed international journals. He is also involved in teaching and numerous professional service activities.
Abstract:
Chemical transformations mediated by transition metals play pivotal role in modern organic chemistry. New reaction development and total synthesis of complex natural products are only a few examples of harnessing the organometallic chemistry. Organozirconium chemistry was successfully utilized in the total synthesis of natural products as exemplified by the recently reported total synthesis of (+)-mucosin. The developed methodology utilized the one-pot two-step zirconocene-mediated co-cyclisation of triene followed by insertion of silylcarbenoid generated in situ, to give the expanded zirconacycle. Protonolysis of zirconacycle followed by the modified Flaming-Tamao oxidation gave the bicyclic alcohol which was oxidized to its corresponding aldehyde by using the Swern protocol. Takaiolefination provided the protected alcohol which was converted to the corresponding carboxylic acid via TBAF deprotection and PDC oxidation. Esterification using diazomethane procedure gave the methyl ester of (+)-mucosin, which is the dextrorotatory enantiomer of the naturally isolated ( )-mucosin methyl ester.
- Advanced trends in organic chemistry | Natural products and heterocyclic chemistry
Location: Flemingo 1&2
Chair
Maria Del Rocio Gamez Montano
Universidad de Guanajuato, Mexico
Co-Chair
Uttam K. Tambar
The University of Texas Southwestern Medical Center at Dallas, USA
Session Introduction
Soon Hyeok Hong
Seoul National University, South Korea
Title: Ruthenium-catalyzed urea synthesis utilizing methanol as the c1 feedstock
Time : 14:05-14:25
Biography:
Soon Hyeok Hong obtained his PhD in 2007 at the California Institute of Technology, under the guidance of Professor Robert H Grubbs. After having Post-doctoral research experience at the University of California, Los Angeles and industrial experiences at Materia, Inc., he began his independent career in academia as an Assistant Professor at Nanyang Technological University with a joint appointment as a National Research Foundation Fellow of the Singapore government in 2008. In 2011, he moved back to his undergraduate school, Seoul National University, where he has been working on organometallic catalysis in developing efficient, practical, and sustainable synthetic methods.
Abstract:
Urea derivatives are commonly found in widespread applications, such as biologically active compounds, pharmaceuticals, agricultural pesticides, dyes for cellulose fibers, and antioxidants in gasoline. Many classical protocols and catalytic transformations have been developed for urea synthesis. Traditional syntheses of urea derivatives use phosgene and isocyanates, which cause tremendous toxicological and environmental problems. Therefore, versatile urea synthesis under mild conditions that avoids environmentally harmful reagents remains a challenge. By applying the concept of acceptorless dehydrogenative coupling, which is a highly advanced environmentally benign strategy for C–O and C–N bond formation directly from alcohols and amines, we developed an unprecedented strategy to synthesize urea derivatives directly from amines utilizing methanol as the C1 source. Symmetrical and unsymmetrical urea derivatives were successfully obtained using methanol as the C1 feedstock. Utilization of methanol as the C1 feedstock could be an ideal solution to reducing the predominant dependence on conventional toxic C1 sources, such as phosgene and isocyanates for urea synthesis.
MarÃa Del RocÃo Gámez Montaño
Universidad de Guanajuato, Mexico
Title: Synthesis of novel tetrazol-chromones via Ugi-azide reaction and in vitro studies for their antibiotic properties
Time : 14:25-14:45
Biography:
Rocío Gámez-Montaño is currently employed at Departamento de Ciencias Naturales y Exactas, Universidad de Guanajuato, Mexico. She was Associate Professor Investigator B during the year 2002-2003 and Associate Professor Investigator C during 2003-2009. She was Chair Professor Investigator A during the year 2009-2015 and Chair Professor Investigator B during the year 2015-present. She completed her Post Doctoral Fellow during (2001-2002) from Institute of Chemistry of Natural Substances, France with Dr. Jieping Zhu. She completed her PhD in Organic Chemistry in the year 2001 from National Autonomous University of Mexico (UNAM).
Abstract:
As a part of our ongoing program to develop short and versatile Ugi-azide based methods toward poly-heterocycles containing the 1,5-disubstituted tetrazole moiety, here I show my resent results about in vitro studies of eighteen newly synthesized tetrazol-chromones against series of pathogenic parasites (Entamoeba histolytica, Giardia lamblia, and Trochomonas vaginalis), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrixschenckii, Candida albicans, and Candida tropicalis). Moderate to good values were found in all cases, however, the best activity was observed in iodine-containing analogues against G. lamblia and C. albicans. These results have been published recently
Nobuyoshi Morita
Showa Pharmaceutical University, Japan
Title: Gold(I)/(III)-catalyzed synthesis of 2-substituted piperidines; valency-controlled cyclization modes
Time : 14:45-15:05
Biography:
Nobuyoshi Morita has completed his PhD from Osaka University in the year 2003 and then trained as a Post-doctoral fellow at Dortmund University of Technology in Germany (Prof. Norbert Krause). He was then recruited as an Assistant Professor of Organic Chemistry in Showa Pharmaceutical University (SPU) in 2006 and became an Associate Professor of Organic Chemistry in SPU in the year 2016. His researches focus on gold catalyzed reactions
Abstract:
Gold catalysts were initially recognized as ï°-acidic catalysts that activate unsaturated bond (alkynes, allenes and alkenes) for nucleophilic attack to form C-C, C-O, C-N, and C-S bonds. Later, some groups reported the oxophilic character of gold (III) catalysts, which efficiently activated oxygen functinalities even in the presence of an unsaturated bond. We rationalized these observations in terms of the hard and soft acids and bases (HSAB) principle, which states that metal ions in low valence states soft character, whereas metal ions in high positive oxidation states show hard character. Thus, gold(I) catalysts may behave as soft acids and gold (III) catalysts as hard acids. On the basis of this working hypothesis, we developed a synthetic method to obtain two types of cyclic ethers from the same propargylic alcohols by means of valency-controlled gold-catalyzed regiodivergent activation. In order to extend our strategy, we turned our attention to the use of nitrogen nucleophile in place of oxygen nucleophile and explored the synthesis of piperidines from propargylic alcohols bearing nitrogen functionality at the terminal position. Thus, use of hard gold (III) catalyst which resulted in cyclization to furnish piperidines having an acetylenic moiety, due to coordination of hard gold (III) to the oxygen atom at propargylic position. On the other hand, treatment of propargylic alcohols with soft gold (I) catalyst induces Meyer-Schuster rearrangement to afford ï¡,ï¢-unsaturated ketones, which undergo intra-molecular aza-Michael addition to give piperidines bearing carbonyl gorup, due to the activation of the triple bond by coordination of soft gold(I).
Uttam K Tambar
The University of Texas Southwestern Medical Center at Dallas, USA
Title: Allylic functionalization of unactivated hydrocarbons
Time : 15:05-15:25
Biography:
Uttam K Tambar received his AB degree from Harvard University in 2000 and his PhD from the California Institute of Technology in 2006 with Professor Brian Stoltz. After he completed his NIH Post-doctoral Fellowship at Columbia University with Professor James Leighton in 2009, he began his independent research career at UT Southwestern Medical Center in Dallas. He is currently an Associate Professor in the Biochemistry Department, a W W Caruth, Jr. Scholar in Biomedical Research, and a Sloan Research Fellowship. He is interested in asymmetric catalysis, natural product synthesis and medicinal chemistry
Abstract:
We have been exploring the selective functionalization of unactivated hydrocarbons. We have developed a catalytic enantioselective allylic amination of unactivated olefins via a [2,3]-rearrangement (Scheme 1). In this method, a diimido-sulfur reagent serves as the source of nitrogen, and it reacts selectively with terminal olefins through a hetero-ene reaction. The resulting zwitterionic ene adduct undergoes a Pd-catalyzed enantioselective [2,3]-rearrangement to generate chiral amines in high enantiomeric excess. Our approach is conceptually distinct from other enantioselective allylic amination strategies. The synthetic utility of our process is being explored by converting simple and inexpensive terminal olefins into functional materials, such as the pharmaceutical drugs Vigabatrin and Januvia. Based on this chemistry, we have also developed a copper-catalyzed allylic alkylation of unactivated olefins and dienes (Schemes 2 and 3). This represents a general method for functionalizing unactivated hydrocarbons with aromatic, aliphatic, and vinyl Grignard reagents. Our recent discoveries represent a conceptual framework for the generalized functionalization of unactivated olefins.
P K Bhowmik
University of Nevada Las Vegas, USA
Title: Synthesis, optical spectroscopy and laser potential of pyrylium tosylates
Time : 15:25-15:45
Biography:
P K Bhowmik is currently a Professor of Chemistry in the Department of Chemistry and Biochemistry at University of Nevada Las Vegas. He received the 2014 POLY Fellow and 2014 ACS Fellow Awards for his outstanding scientific/professional accomplishments and service to the American Chemical Society. He presently serves on the Editorial Board of 10 technical journals and is an academic Editor for Trends in Green Chemistry, Advances in Research, American Chemical Science Journal and Green and Sustainability Chemistry, and as well as an Advisory Board Member for InnoSense LLC, California, USA.
Abstract:
Pyrylium salts are an important class of organic molecules containing trivalent oxygen atom in six-membered aromatic ring. Versatile methods for the synthesis of a series of four 2,4,6-triaryl-substitued pyrylium tosylate salts with different substituents are reported. The synthesis methods use p-toluenesulfonic acid monohydrate instead of conventional acid catalysts including perchloric acid or boron trifluoride diethyl etherate that pose explosion danger and difficult storage problem, respectively. The chemical structures of these salts were established using Fourier transform infrared, 1H and 13C nuclear magnetic resonance spectroscopic techniques and elemental analysis. Their solubility in different organic solvents was dependent on the substituents in 2nd and 6th positions of phenyl groups. Their thermal stability and thermal property were studied using thermogravimetric analysis and differential scanning calorimeter, respectively. It was observed that, solutions of all four pyrylium tosylate salts absorbed strongly in the blue-near-ultraviolet spectral range and emitted efficiently in the blue-green spectral range depending on the substituent in 2nd and 6th positions of phenyl groups. The fluorescence quantum yield of the salts ranged from 0.56 to 0.33 and under intense ultrashort laser pumping, the solution of the salt, (2,4,6-triphenylpyrylium tosylate), which was having the highest quantum yield demonstrated stimulated emission and laser action with only nominal feedback.