Seminars 2017

Title: Development of Precisely Designed Chemoselective Catalysis
Speaker:Professor Ryo Yazaki
Date:12th December 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Shunsuke Chiba 
Abstract: 

Catalyst-controlled chemoselective reactions offer new opportunities for minimal reliance on protecting groups even in the presence of innately more reactive functionalities. Despite the prospects for contributions to both atom and step economy of catalyst-controlled chemoselective reactions, progress in this area has been limited relative to catalyst-controlled stereo or regioselective reactions. Recent our contribution for the development of chemoselective catalysis, such as conjugate addition, amination/oxidation and oxidative cross coupling, will be presented.

Title: Organic TADF Emitters for Light-Emitting Electrochemical Cells and Organic Light-Emitting Diodes
Speaker:Professor Eli Zysman-Colman
Date:28th November 2017
Time:2.00pm to 3.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Assistant Professor Soo Han Sen 
Abstract: 

The first generation OLEDs were based on organic fluorescent emitters. Their efficiency was intrinsically capped at 25% due to only being able to recruit singlet excitons. The second generation OLEDs have employed organometallic phosphorescent emitters, which harvest both singlet and triplet excitons for emission due to the enhanced intersystem crossing mediated by the heavy metals such as iridium(III) and platinum(II). These metal complexes possess very desirable optoelectronic properties and lead to very efficient OLED devices. However, the rarity of these metals, their high cost and their toxicity are important detracting features that inhibit large-scale, worldwide adoption of OLED technology, particularly for lighting where, unlike displays, low cost devices are crucial to market growth. The third generation OLEDs are based on small organic compounds that emit via a thermally activated delayed fluorescence (TADF) mechanism. As with phosphorescent emitters, OLEDs using these emitters can recruit 100% of the excitons. In this presentation, I will present our efforts towards emitter design, particularly targeting blue emission, in OLED architectures, which is a grand challenge in solid-state lighting. I will also present the first examples of organic TADF emitters in light-emitting electrochemical cells.

Title: Quantum chemistry in ligand directed catalysis
Speaker:Dr Adrian Mak
Date:8th November 2017 
Time:2.30pm to 4.00pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Assistant Professor Loh Zhi Heng
Abstract: 

The synthesis of speciality chemicals for various applications — pharmaceuticals, natural products, agrochemicals, polymers — often require methods to activate carbon-hydrogen bonds in one substrate, and subsequently form carbon-carbon, carbon-nitrogen, and carbon-halogen bonds with others. Desirable catalysts offer high product selectivity, wide substrate scope, appreciable yield, and mild operating conditions for these chemical transformations. In collaboration with groups from A*STAR’s Institute of Chemical Engineering & Sciences (ICES) and Singapore Bioimaging Consortium (SBIC), two families of ligands, namely, a meta-terarylphosphine ligand *Phine, and functionalized thioamides were developed, and analyzed. The *Phine-directed catalysis of aromatic fluorination, copper-free Sonogashira coupling, and N-arylation, along with the thioamide-directed selective activation of C(sp3)-H were investigated using ab initio and density functional methods, results of which will be presented and discussed. Insights from these studies contribute to systematic optimization of ligands that in turn shorten the design cycle of catalysts.

Title: Restoring programmed cell death through MCL1 Inhibition
Speaker:Dr András Kotschy
Date:7th November 2017
Time:2.00pm to 3.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Roderick Bates
Abstract: Tumor cells that harbor genetic mutations and are recognized as abnormal should be naturally eliminated but they maintain their existence by a combination of multiple activities – also known as the hallmarks of cancer [1] . One of these hallmarks is the evasion of apoptosis, the programmed cell death. The restoration of the apoptotic cascade in tumor cells has long been recognized as a promising way to treat cancer but the major members of this protein family, BCL2, MCL1, and BCL-xL have long remained elusive targets decades long for drug discovery. Recently the decade long efforts of the pharmaceutical industry have been rewarded by the identification of potent and selective inhibitors for some family members [2] . The presentation overviews the principal pharmacological and chemical challenges of targeting this protein family and presents the recent scientific [3] and pharmacological achievements in this area. [1] D. Hanahan, R.A. Weinberg Cell, 2011, 144, 646. [2] A. Ashkenazi, W.J. Fairbrother, J.D. Leverson, A.J. Souers Nature Reviews in Drug Discovery, 2017, 16, 273. [3] A. Kotschy, Z. Szlávik, J. Murray et al. Nature, 2016, 538, 477.
Title: Photonic and Magnetic Nanoparticles and Nanoscale "Teflon" Coatings
Speaker:Professor T. Randall Lee
Date:6th November 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Zhao Yanli 
Abstract: An emerging class of photonic nanoparticles can be prepared with systematically tunable absorptions ranging from visible to near infrared (NIR) wavelengths. These nanoparticles serve as versatile nanoscale tools, where the particles can be optically detected/modulated by irradiation with NIR light. This presentation will highlight the preparation, characterization, and applications of hollow "nanoshell" particles that possess a variety of dimensions, chemical compositions, and optical properties. In particular, current synthetic strategies allow the preparation of NIRactive nanoshells that possess diameters as small as 40 nm, which opens the door to new medical diagnostics and therapies, as well as unique opportunities in the energy sector, where such nanoshells offer unique benefits in plasmon-enhanced solar conversion. Separate studies targeting the development of cubic and spherical magnetic nanoparticles for biosensing will also be described; importantly, our studies have found cubic magnetic nanoparticles to offer a variety of advantages when compared to the more widely utilized spherical magnetic nanoparticles. A third topic will focus on fluorinated organic thin films, with an emphasis on understanding the minimum degree of fluorination required to give nanoscale "Teflon-like" coatings.
Title: Extreme Imaging for Large-Scale Single-Cell Analysis
Speaker:Professor Keisuke Goda
Date:25th October 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Dr Ronald Ulbricht (Postdoc in Asstiant Prof Loh Zhi Heng’s group)
Abstract: Cellular heterogeneity is a central challenge of biology in which there are cell-to-cell differences even within the same species. Populationaveraged measurements of cellular behaviors do not represent the behaviors of any individual cell. A few notable examples of cellular heterogeneity are the resistance of cancer cells to anticancer drugs and the metabolic heterogeneity of microorganisms. In this talk, I present extremely fast multi-modal imaging technology combined with artificial intelligence on a microfluidic platform for large-scale single-cell analysis. The imaging technology is enabled by an integration of three world’s-fastest imaging modalities (bright-field, fluorescence, Raman) based on optical frequency combs. It provides information-rich images of numerous single cells in a short period of time to address and exploit cellular heterogeneity. In the talk, I discuss the principles and various applications of the technology.
Title: Well-defined siloxane materials: past and present
Speaker:Professor Masafumi Unno
Date:19th October 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Rei Kinjo
Abstract: 

Synthesis of well-defined silsesquioxanes is now strongly desired especially from the industry because of recent high demanding to materials. Unlike conventional approach, we mostly control the structure of starting materials for the sake of the selective synthesis. Cyclic silanols possess multiple hydroxyl groups in the molecule, and potential precursors to well-defined silsesquioxanes. We prepared many novel cyclic silanols,1 and prepared cage, partial-cage, and ladder silsesquioxanes. 2 It is noteworthy that these silsesquioxanes shows expected high stability (thermal and photo- and radiochemical) as well as some unusual properties. Detailed synthesis and properties of these silsesquioxanes based on our fundamental research in the last two decades, and very recent results are summarized in the presentation.

References 1. (a) M. Unno, Y. Kawaguchi, Y. Kishimoto, and H. Matsumoto, “Stereoisomers of 1,3,5,7-Tetrahydroxy-1,3,5,7-tetaisopropylcyclotetrasiloxane: Synthesis and Structures in the Crystal”, J. Am. Chem. Soc., 127, 2256–2263 (2005); (b) M. Unno, H. Endo, and N. Takeda, Synthesis and Structures of Extended Cyclic Siloxanes, Heteroatom Chem. 25, 525–532 (2014). 2. (a) N. Oguri, Y. Egawa, N. Takeda, and M. Unno, Janus-Cube Octasilsesquioxane: Facile Synthesis and Structure Elucidation, Angew. Chem. Int. Ed. 55, 9336-9339 (2016); (b) M. Unno, A. Suto, and T. Matsumoto, "Laddersiloxanes— Silsesquioxanes with defined ladder structure", Russ. Chem. Rev., 82, 289–302 (2013).

Title: Recent progress in the chiral phosphoric acid catalysis
Speaker:Professor Takahiko AKIYAMA
Date:9th October 2017
Time:10.30am to 12.00pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tan Choon Hong  
Abstract: Chiral phosphoric acid, derived from (R)-BINOL, has been recognized as highly efficient chiral Brønsted acid catalyst, which controls the stereochemistry based on the hydrogen bond network by using the Brønsted acidic part and Lewis basic part. In this lecture we will discuss discovery of the chiral phosphoric acid catalyst and recent progress in the chiral phosphoric acid catalysis, such transfer hydrogenation of imines and construction of chiral biaryl structure.
Title: Luminescent sensors and optical switches for intracellular signaling analysis
Speaker:Professor Takeaki Ozawa
Date:29th September 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Xing Bengang 
Abstract:

Engineered fluorescent and bioluminescent proteins are now widely used for analysis of small molecules and various intracellular events in live cells. The luminescent proteins are entirely genetically encoded and can be engineered to generate functional probes. I herein describe a novel design of engineered fluorescent proteins and luciferases for the analysis of intracellular signaling; the principle is based on complementation and reconstitution of the split-reporter fragments when they are brought sufficiently close together. To demonstrate the usefulness of the split reporters, I will focus on the methods for imaging dynamics of RNAs and different apoptotic signals in a single living cells. I also show novel techniques of bioluminescence imaging of GPCRs and caspase activation in vivo. In addition to the imaging technologies, an optogenetic tool for controlling a kinase activity with external light will be discussed. These less-invasive techniques are widely applicable for understanding complex biological systems with high spatiotemporal resolution.

Title: Imaging Fluorescent DNA interactive probes in cells Where is the drug gone?
Speaker:Dr. Marie-Paule Teulade-Fichou
Date:15th September 2017
Time:11.00am to 12.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Shao Fangwei
Abstract:

For many years our research efforts have been focused on the design of structure and fluorescent probes for nucleic acids. 1,2 In particular we are interested in targeting DNA domains containing base repeats likely to form secondary structures that are involved in dysfunctions related to cancer developments. Our aims are two-folded i) providing mechanistic tools and imaging probes ii) identifying new anticancer drug candidates. We will present last developments in this field using two examples of DNA-targeted drugs e.g. phenanthroline derivatives binding quadruplex DNA and triphenylamine derivatives binding minor groove of B-DNA. Synthesis, chemical methodologies for drug labelling2 and drug localisation using various imaging microscopies (one and two-photon fluorescence and chemical imaging)3,4 will be presented. We will also address in both cases the issues related to drug localisation in live cells. 5

1. E. Largy, A.Granzhan, D.Verga, F.Hamon, M.-P. Teulade-Fichou Topics in Current Chem. 2013, Vol 330, 111-177, Special issue Quadruplex Nucleic Acids. Springer Berlin Heidelberg, Berlin, Heidelberg. 2. B. Dumat, G. Bordeau, E. Faurel-Paul, F. Mahuteau-Betzer, N. Saettel, G. Metge, C. Fiorini-Debuisschert, F. Charra, M.-P. Teulade-Fichou. J.Amer.Chem.Soc. 2013, 135, 12697-12706 . 3. J. Lefebvre, F.Poyet, C.Guetta, F.Mahuteau-Betzer, M.-P. Teulade-Fichou. Angewandte Chemie Int.Ed. 2017, vol 57, 2017, Vol 56, 1-16. 4. D.Verga, T.D. Wu, J.-L. Guerquin-Kern, M.-P. Teulade-Fichou, S.Marco, J. Molecular Biology and Molecular Imaging 2017, in press. 5. R. Chennoufi , H. Bougherara, N. Gagey-Eilstein, B. Dumat, E. Henry, F. Subra, S. Bury-Moné, F. Mahuteau-Betzer, P.Tauc, M.-P. TeuladeFichou, E. Deprez. Scientific Reports 2016 , 6 (21458), 1-12.

Title: Application of Vinylindoles and Indolylmethanols in Synthesizing Indole Derivatives
Speaker:Professor Feng Shi
Date:15th September 2017
Time:2.30pm to 4.00pm  
Venue:SPMS MAS Executive Classroom 1
Host:Professor Robin Chi  
Abstract:

Catalytic asymmetric synthesis of enantioenriched indole derivatives has aroused great concern in the community of chemistry because chiral indole frameworks constitute the core structures of many important natural products and pharmaceuticals.1 Among different approaches, catalytic asymmetric reactions using vinylindoles and indolylmethanols as reactants have recently emerged as powerful methods for synthesizing optically pure indole derivatives.2 However, new class of vinylindoles and indolylmethanols-involved catalytic asymmetric reactions are rather limited, which remains to be a great challenge in organic synthesis. To settle this challenge, our group has designed new class of vinylindoles and indolylmethanols as competent reactants for catalytic asymmetric reactions, which synthesized a variety of enantioenriched indole derivatives.3-4 For instance, we have designed 3-alkyl-2- vinylindoles and established [n+2] cyclization, dearomatization and [3+2] cyclodimerization reactions of this class of substrates.3 In addition, we have designed 2-indolylmethanols as 3C building blocks in enantioselective and regioselective [n+3] cycloadditions.4 We also found the interesting “umpolung” property of the C3-position of 2-indolylmethanols, which facilitated a series of indole-nucleophile couplings.4 In this lecture, I will give more details on the recent advances of our group in this research filed.

References 1. For some recent reviews: (a) Kochanowska-Karamyan, A. J.; Hamann, M. T. Chem. Rev. 2010, 110, 4489; (b) Taber, D. F.; Tirunahari, P. K. Tetrahedron 2011, 67, 7195. 2. For some recent reviews: (a) Chen, Y.; Wang, L.; Xiao, J. Asian J. Org. Chem. 2014, 3, 1036; (b) Wu, H.; He, Y.-P.; Shi, F. Synthesis, 2015, 47, 1990. 3. For a recent review: (a) Mei, G.-J.; Shi, F. Synlett, 2016, 27, 2515; For some examples: (b) Tan, W.; Li, X.; Gong, Y.-X.; Ge M.-D.; Shi, F. Chem. Commun. 2014, 50, 15901; (c) Zhao, J.-J.; Sun, S.-B.; He, S.-H.; Wu, Q.; Shi, F. Angew. Chem. Int. Ed. 2015, 54, 5460. 4. For a recent review: Mei, G.-J.; Shi, F. J. Org. Chem. 2017, 82, 7695; (a) For some examples: (b) Sun, X.-X.; Zhang, H.-H.; Li, G.-H.; He, Y.-Y.; Shi, F. Chem. Eur. J. 2016, 22, 17526; (c) Zhu, Z.-Q.; Shen, Y.; Sun, X.-X.; Tao, J.-Y.; Liu, J.-X.; Shi, F. Adv. Synth. Catal. 2016, 358, 3797; (d) Zhang, H.-H.; Wang, C.-S.; Li, C.; Mei, G.-J.; Li, Y.; Shi, F. Angew. Chem. Int. Ed. 2017, 56, 116.

Title: Practical and Scalable Total Synthesis of Complex Natural Product through Sequential C-H Functionalizations
Speaker:Professor Lei Xiaoguang
Date:5th September 2017
Time:11.00am to 12.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Associate Professor Xing Bengang 
Abstract:

Structurally complex and bioactive natural products provide tremendous opportunities to shape the landscape of organic synthesis, as well as to impact the biomedical research and drug discovery. My laboratory conducts research at the interface between chemistry and biology. We systematically use bioactive small molecules, particularly natural products, to study their biological functions, elucidate molecular mechanisms of the important biological pathways, and develop novel therapeutic agents for currently intractable diseases. However, traditionally total synthesis of complex natural product could only provide small quantity of material, which significantly hinders the subsequent application. Therefore, the ability to procure useful quantities of complex molecules by simple, scalable routes is emerging as an important goal in natural product synthesis. Selective C-H functionalization has emerged as an ideal tool for organic synthesis for the past decade, yet chemists still struggle to apply the newly developed synthetic methodology to construct complex and highly functionalized molecules through a practical process. Therefore, the development of conceptually new approach using selective C-H functionalization catalysis is of particular interest and will ultimately enable synthetic chemist to obtain sufficient quantities of complex molecules for further biological studies. Herein, I would like to disclose our recent endeavors towards the practical and scalable total syntheses of a number of interesting natural products through selective and sequential C-H functionalization catalysis.

Title: Chemo, Regio and Stereoselective Organic Transformations of 1,1-Diborylalkanes
Speaker:Professor Seung Hwan Cho
Date:31st August 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Naohiko Yoshikai 
Abstract:

1,1-Organodimetallic reagents are valuable starting materials for the construction of multifunctionalized molecules. Among them, 1,1- diborylalkanes, which contain two boryl groups at the same carbon center, are particularly attractive due to their ease of handling, non-toxicity, stability, and propensity to undergo a variety of organic transformations. In this context, our lab is highly interested in the development of regio, chemo and stereoselective organic reactions using 1,1-diborylalkanes as new types of organodimetallic reagents. In this seminar, the details about our recent findings using 1,1-diborylalkanes in a range of organic transformations will be presented. 1-7

References (1) Kim, J.; Park, S.; Park, J.; Cho, S. H.* Angew. Chem., Int. Ed. 2016, 55, 1498. (2) Park, J.; Lee, Y. Kim, J. Cho, S. H.* Org. Lett. 2016, 18, 1210. (3) Cho, W.; Kim, J.; Choi, S. Cho, S. H.* Angew. Chem., Int. Ed. 2016, 55, 9690. (4) Lee, Y.; Baek, S.; Park, J.; Kim, S. T.; Tussupbayev, S.; Kim, J.; Baik, M. Cho, S. H.* J. Am. Chem. Soc. 2017, 139, 976. (5) Park, J.; Choi, S.; Lee, Y. Cho, S. H.* Org. Lett. 2017, 19, 4054. (6) Hwang, C.; Jo, W.; Cho, S. H.* Chem. Commun. 2017, 53, 7573. (7) Kim, J.; Ko, K.; Cho, S. H.* Angew. Chem., Int. Ed. 2017, in press.

Title: Photocatalytic Conversion of Alcohols for Selective Chemical Synthesis
Speaker:Professor Hiroshi Naka
Date:10th August 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Naohiko Yoshikai 
Abstract:

Catalytic selective synthesis is one of the primary challenges in modern synthetic organic chemistry. This presentation will introduce our recent effort towards this goal in developing chemoselective methods using alcohols and metal oxide photocatalysts. These methods enable borrowing-hydrogen-type reactions to proceed at around room temperature, including dehydrogenation of primary alcohols to aldehydes, hydrogenolysis of allylic alcohols, and N-alkylation of amines with alcohols.

Title: Systematic determination of complex reaction mechanisms
Speaker:Dr W M C Sameera
Date:8th August 2017
Time:10.00am to 11.30am 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tan Choon Hong 
Abstract:

Transition metal catalysis is an efficient way to perform catalytic reactions in a controlled and a selective fashion. Quantitative details of mechanisms and selectivity of catalytic reactions are very important for the development of more efficient catalysis. These properties are however difficult to characterize from experimental studies alone, and therefore computational chemistry becomes critical. 1,2 The traditional computational methods for the study of potential energy surfaces (ground or excited states) require manual trial-and-error and guess-andcheck processes. However, this strategy may miss some important or unexpected reaction paths. Therefore, new computational methods for comprehensive and systematic study of potential energy surfaces are crucial. In this direction, the artificial force induced reaction (AFIR) method is very useful. 3,4 The AFIR method determines equilibrium structures and subsequent reaction paths systematically, and therefore comprehensive description of the reaction mechanism and selectivity can be achieved.

I present mechanistic puzzles in transition metal-catalyzed aziridination,5-7 where minimum energy seam crossing points between the singlet and triplet potential energy surfaces control the selectivity. Also, I will discuss AFIR applications that targeted the selectivity-determining step of transition metal catalyzed asymmetric carbon-carbon8 and carbon-boron9,10 bond formation reactions. My computational studies offer important mechanistic insights to develop broadly applicable catalytic reactions for potential applications in industry and academia.

References 1. W. M. C. Sameera, F. Maseras, WIREs Comput. Mol. Sci., Wiley-VCH, 2012, 2, 375-380. 2. L. W. Chung, W. M. C. Sameera, R. Ramozzi, A. J. Page, M. Hatanaka, G. P. Petrova, T. V. Harris, X. Li, Z. Ke, F. Liu, H-B. Li, L. Ding, K. Morokuma, Chem. Rev. 2015, 115, 5678-5786. 3. W. M. C. Sameera, S. Maeda, K. Morokuma, Acc. Chem. Res. 2016, 49, 763-773. 4. W. M. C. Sameera, A. K. Sharma, S. Maeda, K. Morokuma, Chem. Rec., 16, 2016, 2349-2363. 5. J. Llaveria, Á. Beltrán, W. M. C. Sameera, A. Locati, M. M. Díaz-Requejo, M. I. Matheu, S. Castillón, F. Maseras, P. J. Pérez, J. Am. Chem. Soc. 2014, 136, 5342-5350. 6. L. Maestre, R. Dorel, O. Pablo, I. Escofet, W. M. C. Sameera, E. Álvarez, F. Maseras, M. M. Diaz-Requejo, A. M. Echavarren, P. J. Pérez, J. Am. Chem. Soc. 2017, 139, 2216-2223. 7. L. Maestre, W. M. C. Sameera, M. M. Díaz-Requejo, F. Maseras, P. J. Pérez. J. Am. Chem. Soc. 2013, 135, 1338-1348. 8. W. M. C. Sameera, M. Hatanaka, T. Kitanosono, S. Kobayashi, K. Morokuma, J. Am. Chem. Soc. 2015, 137, 11085-11094. 9. Y. Takeda, A. Kuroda, W. M. C. Sameera, K. Morokuma, S. Minakata, Chem. Sci. 2016, 7, 6141-6152. 10. M. Isegawa, W. M. C. Sameera, A. Sharma, T. Kitanasano, M. Kato, S. Kobayashi, K. Morokuma, ACS Catal. (In press) DOI: 10.1021/acscatal.7b01152

Title: Synthesis of Nitrogen-Containing Polyarenes Using Polycyclic Aromatic Azomethine Ylides
Speaker:Professor Shingo Ito
Date:7th August 2017
Time:10.00am to 11.30am 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tan Choon Hong 
Abstract:

Introduction of nitrogen atoms into polycyclic aromatic hydrocarbons (PAHs) have received much attention because it significantly alters the intrinsic properties of PAHs. However, the variety of accessible nitrogen-containing PAHs is still limited. Here I introduce our recent research on the synthesis and properties of novel polycyclic aromatic azomethine ylides (PA-AMYs) and their applications to the synthesis of various planar and bowl-shaped nitrogen-containing PAHs. The lecture consists of the following three topics: 1) synthesis and properties of PA-AMYs, 2) 1,3- dipolar cycloaddition of PA-AMYs with various alkenes and alkynes to form corresponding pyrrolidine and pyrrole derivatives, and 3) synthesis and applications of novel azacorannulene derivatives.

Title: Recent Progress on Attosecond Science at RIKEN
Speaker:Professor Katsumi Midorikawa
Date:1st August 2017
Time:4.00pm to 5.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Assistant Professor Loh Zhi Heng 
Abstract:

Since the first observation of high-order harmonic generation (HHG) around 1987, almost thirty years have passed. HHG is now established as a high-output coherent light source in the XUV region and the sole source of attosecond pulses. Here, I review our recent efforts on attosecond science by intense high harmonics including the extension of high harmonic cutoff to the sub-keV region by using new pump laser technology developed at RIKEN. Our attosecond light source, a-few-pulse attosecond pulse train with a moderate spectral bandwidth, is a unique device for measuring ultrafast quantum dynamics in a molecule because it allows us to achieve sufficiently high intensity for performing attosecondpump/ attosecond-probe measurements with moderate statistics and a sufficiently high spectral resolution for identifying the relevant states. We implemented attosecond-pump/ attosecond-probe scheme with this source to measure the electronic and vibrational response of diatomic molecules in the intrinsic timescale of the electron.

Title: Nanophotonics – From Simulations, Photophysics, to Biomedical Devic
Speaker:Professor Shuang Fang Lim
Date:17th July 2017
Time:11.00am to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Xing Bengang 
Abstract:

Rare earth ion doped upconverting nanoparticles are excited in the near infrared (NIR) and fluoresce via Anti-stokes emission in the visible energy range (400-650 nm). They show large penetration depth of excitation, no blinking, and high signal-to-noise ratio due to zero tissue autofluorescence. In addition, since upconversion is a two-photon fluorescence process, it has the same ability as other 2-photon fluorescence microscopies to resolve the 3-dimensional structure of objects. Despite the fundamental advantages that UCNPs have over semiconductor nanoparticles and molecular dyes, they have not been used widely due to their comparatively low brightness and low upconversion efficiency at low pump powers.

Our upconversion nanostructures are optimized with predictive finite element modeling, and correlated structural and optical single nanoparticle spectroscopy is performed to explore the link between nanostructure orientation, geometry and the corresponding nanoparticle optical property. Investigation of the enhancement at the single particle level is directly relevant to this work because the effect of the modifications can be explained both quantitatively and qualitatively. The single particle results are also more consistent with finite element calculations, without having to correct for anomalies generated by ensemble measurements.

The optimized nanostructures are applied in the sensing of protein translocation and specific DNA binding events, at high spatial resolution.

Title: Reversible Reservoirs for Radicals. A Powerful Strategy for the Construction of Carbon-Carbon Bonds
Speaker:Professor Samir Zard
Date:12th July 2017
Time:11.00am to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Shunsuke Chiba 
Title: From Steroids to Radicals. The Wanderings of a Curious Chemist
Speaker:Professor Samir Zard
Date:10th July 2017
Time:2.00pm to 3.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Shunsuke Chiba
Title: Organocatalyzed Reductive Amination of Aldehydes and Ketones with Trichlorosilane
Speaker:Professor Pavel Kočovský
Date:23rd June 2017
Time:11.00am to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tamio Hayashi
Title: Donor-acceptor Stabilization of Main Group Species: From New Bonding Environments to Nanomaterials
Speaker:Professor Eric Rivard
Date:22nd June 2017
Time:11.00am to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Naohiko Yoshikai 
Abstract:

In this presentation, a general-donor-acceptor protocol will be introduced to intercept reactive main group species, such as the parent hydrides EH2 and H2EEH2 (E = Si, Ge and/or Sn),[1] the iminoborane HBNH[2] and oxoboranes (e.g. ClB=O and HOB=O). [3] The reported EH2 complexes are viable precursors to luminescent nanomaterials[4]while the latter oxoborane adducts can instigate mild C-F activation processes. Moreover our recent efforts[5] to develop highly bulky carbon-based donors will be described.

[1] For a review article, see: E. Rivard, Chem. Soc. Rev. 2016, 45, 989-1003. [2] a) A. K. Swarnakar, C. Hering-Junghans, K. Nagata, M. J. Ferguson, R. McDonald, N. Tokitoh, E. Rivard, Angew. Chem., Int. Ed. 2015, 54, 10666-10669; b) A. K. Swarnakar, C. Hering-Junghans, M. J. Ferguson, R. McDonald, E. Rivard, Chem. Sci. 2017, 8, 2337-2343. [3] A. K. Swarnakar, C. Hering-Junghans, M. J. Ferguson, R. McDonald, E. Rivard, Chem. Eur. J. 2017, DOI: 10.1002/chem.201702154. [4] T. K. Purkait, A. K. Swarnakar, G. B. De Los Reyes, F. A. Hegmann, E. Rivard, J. G. C. Veinot, Nanoscale 2015, 7, 2241-2244. [5] C. Hering-Junghans, P. Andreiuk, M. J. Ferguson, R. McDonald, E. Rivard, Angew. Chem., Int. Ed. 2017, 56, 6272-6275.

Title: The Mechanical Bond: Mingling Art with Science
Speaker:Professor Sir Fraser Stoddart
Date:19th June 2017
Time:3.00pm to 4.30pm 
Venue:SPMS Lecture Theatre 1
Host:Associate Professor Zhao Yanli 
Title: Chemoselective Protein Modifications Based on Organoradicals
Speaker:Professor Kounosuke Oisaki
Date:6th June 2017
Time:3.00pm to 4.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Assistant Professor Rei Kinjo 
Abstract:

Chemical modification of peptides and proteins targeting naturally occurring amino acid residues opens up a wide range of applications such as modulation/tracking of biological phenomena, creation of biocompatible materials and new therapeutics. However, there is a considerable shortage of methods to convert proteins with high flexibility and selectivity. Recently, we have developed two kinds of reaction systems that proceed with proteinogenic amino acid (serine or tryptophan) selectivity. In the course of research, we strategically focused on organic radical species that exhibit high reactivity and functional group tolerance. In this lecture, I am willing to share our research background, recent progress and potential applications of the novel reactions.

Title: Emerging Guidelines for the Design of Novel Organic Semiconductors
Speaker:Professor Guillermo C. Bazan
Date:26th May 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Zhao Yanli
Abstract:

This presentation will cover some emerging ideas in our laboratories for designing organic semiconductors with properties that make them relevant for the fabrication of organic field effect transistors and transparent solar cells. In particular, we will discuss regioregular conjugated polymers. When processed atop nanostructured substrates under slow solvent evaporation, it is possible to obtain thin films with a very high degree of structural order that can be used to fabricate p-type thin film transistors with very high mobilities. We will discuss how to control charge injection in these devices through both polymer structure design, and through the intentional addition of traps that are specific for either holes or electrons.

A general synthetic methodology will also be provided that can be applied for the preparation of more complex polymer architectures, for example a backbone comprised of CPDT-PT-IDT-PT repeat units (CPDT = cyclopentadithiophene, IDT = indacenodithiophene, PT = pyridyl[2,1,3]thiadiazole) and strictly organized PT orientations, such that the pyridyl N-atoms point toward the CPDT fragment. When incorporated into bulk heterojunction solar cells, the CPDT-PT-IDT-PT copolymer, namely PIPCP, is noteworthy because the open circuit voltage is particularly high for a donor polymer with a band gap < 1.5 eV. One therefore finds very low energy losses relative to the optical gap of the semiconductor. How PIPCP is capable of achieving current generation under limiting thermodynamic conditions was examined through a combination of structural and optical characterization techniques. An overall perspective of the mechanism will be discussed.

Title: Agonies and Ecstasies in Syntheses of Natural Products
Speaker:Professor Krishna P. Kaliappan
Date:25th May 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Roderick Bates 
Abstract:

Our group has been engaged in designing simple and efficient synthetic strategies for the syntheses of biologically active natural products and natural product like molecules. In this lecture, our efforts leading to syntheses of vinigrol, dolabriferol, palmerolides and a few more natural products will be discussed in details.

Selected Recent References: 1. K. Ramakrishna, K. P. Kaliappan “An Enantioselective Total Synthesis of Sch-725674” Org. Biomol. Chem. 2015, 13, 234-240. 2. V. V. Betkekar, A. Sayyad, and K. P. Kaliappan, “A Domino Enyne/IMDA Approach to the Core Structure of (-)-Vinigrol” Org. Lett., 2014, 16, 5540-5543. 3. V. D. Goud, Kaliappan, K. P. “Total Syntheses of Rubiginone A2, C2, and Fujianamycin A” RSC Adv., 2014, 4, 12176-12722. 4. V. V. Betkekar, S. Panda and K. P. Kaliappan "A Tandem Enyne/Ring Closing Metathesis Approach to 4-Methylene-2- cyclohexenols: An Efficient Entry to Otteliones and Loloanolides" Org. Lett., 2012, 14, 198-201. 5. K. Palanichamy A. V. Subrahmanyam and K. P. Kaliappan "A Radical Approach to Formal Total Syntheses of Platencin". Org. Biomol. Chem. 2011, 9, 7877-7886. 6. P. Gowrisankar, S. A. Pujari and K. P. Kaliappan, “A Formal Total Synthesis of Palmerolide A” Chem. Eur. J. 2010, 16, 5858- 5862

Title: Practical Asymmetric Hydrogenation
Speaker:Professor Zhang Xumu
Date:3rd May 2017
Time:10.30am to 12.00pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tan Choon Hong 
Abstract:

Dr. William Knowles, in his 2001 Nobel Lecture, describes his 1960s and 70s work in developing asymmetric hydrogenation catalysts. Now, 45 years later after the first commercial application of asymmetric catalysis, although major advances have been made (e.g.; Professor Noyori’s Nobel prize winning work in asymmetric hydrogenation), significant challenges remain. This presentation describes innovation in asymmetric hydrogenation catalysis from both an academic and industrial perspective. Having invented a catalyst that addresses an unmet need in asymmetric hydrogenation, many challenges remain before the catalyst provides an economic return. The knowledge gained and shortcomings recognized during scale-up and commercialization can lead to greatly improved ‘next generation’ catalysts. This presentation highlights recent advances in our labs and the commercialization of many chiral phosphine ligands by Chiral Quest, Inc. The broad array of our chiral catalyst toolbox and their numerous applications for a variety of functional group hydrogenations will be reviewed. The emphasis will be on the practical application of asymmetric hydrogenation to make chiral pharmaceutical in ton scale.

Title: Designer Nucleotides for Studying the Repair of DNA Damage
Speaker:Professor Eric Kool
Date:29th March 2017
Time:2.00pm to 3.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Xing Bengang
Abstract:

Here I describe the design and discovery of novel and sensitive nucleotide-based chemical probes that act as luminescence reporters of the cellular activities of enzymes that repair DNA damage. This work began in our lab with the development of novel fluorescent DNA bases, and the use of DNA synthesizers to assemble these designer nucleotides into oligomers that have unusual and useful fluorescence properties.

Our new probe molecules are designed to aid in the study of cancer. Many common cancers remain difficult to treat, including lung, colorectal, and pancreatic cancer, which together account for over 200,000 deaths annually in the U.S. These cancers often misregulate the enzymes that combat DNA damage, including MTH1 and OGG1, which remove 8-OG from the nucleotide pool and from DNA itself. We hypothesize that developing approaches to control the activities of these enzymes will provide new and promising strategies for controlling tumor growth. However, until very recently it has been difficult to measure these enzymes’ activities.

Our aims are to develop new probes to quantify specific repair activities in tumor cells and tissues; to identify and develop new small-molecule modulators of the enzymes; and to test novel biological hypotheses regarding how altering repair activity may suppress tumor growth. We hope that our new molecular tools will be useful to the cancer research community.

Title: How can we transform mono-functional proteins to biosensors?
Speaker:Professor Hiroshi Ueda
Date:13th March 2017
Time:2.00pm to 3.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Xing Bengang
Abstract:

In nature, there are numerous receptor proteins that convert the ligand-binding signal to other signals such as ion torrent and enzyme activity. Here I will introduce our novel approaches to engineer natural mono-functional proteins e.g. binding proteins such as antibody, or bioluminescent protein such as luciferase into biosensors. The first example is Quenchbody, which is a reagentless fluorescent biosensor based on the principle of antigen-dependent removal of a quenching effect on a fluorophore attached to antibody domains1 . This was discovered while analyzing the antibody single chain variable region (scFv) fluorolabeled at the N-terminal region, but later higher response was attained with multi-labeled Fab fragments, probably due to enhanced quenching2 . The second example is FlimPIA (firefly luminescent intermediate-based protein-protein interaction assay), which utilizes the functional complementation of two mutant firefly luciferases3 . If time allows, results of fluorescent protein-based4 and other enzyme-based immunosensors will be shown.

References 1) R. Abe et al., J. Am. Chem. Soc. 133, 17386-17394 (2011). 2) R. Abe et al. Sci. Rep. 4, 4640 (2014). 3) Y. Ohmuro-Matsuyama et al. Anal. Chem. 85, 7935-7940 (2013); ibid. 86, 2013-2018 (2014). 4) C.I. Chung et al., Anal. Chem. 87, 3513-3519 (2015).

Title: Development of Highly Functional Medical Devices by Design of Biointerface
Speaker:Professor Madoka Takai
Date:13th March 2017
Time:12.00pm to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Zhao Yanli
Title: Self-Organized Functional Materials: Liquid Crystals and Organic/Inorganic Hybrids Designed for Energy and Environmental Applications
Speaker:Professor Takashi Kato
Date:13th March 2017
Time:11.00am to 12.00pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Zhao Yanli
Title: Genetic alphabet expansion technology and its diagnostic and therapeutic applications
Speaker:Professor Ichiro Hirao
Date:7th March 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Assistant Professor Shao Fangwei
Abstract:

Genetic alphabet expansion technology by introducing artificial extra bases or base pairs into DNA has rapidly been advanced. Current DNAbased technologies and nucleic acid functionalities are restricted by only four limited types of nucleotide components composed of four letters, A, G, C, and T, as nucleobases with similar chemical and physical properties. Thus, expanding the genetic alphabet could confer novel functionalities or technologies to DNA.

We have succeeded in developing the genetic alphabet expansion using new types of bases, called Ds and Px. The Ds and Px bases selectively pair each other and are highly hydrophobic. The Ds–Px pair functions as a third base pair with high efficiency and selectivity in DNA replication, along with the natural A–T and G–C pairs. DNA fragments containing the Ds−Px pair were amplified ~1028 -fold by 100 cycles of PCR (10-cycle PCR and dilution process was repeated 10 times), and more than 97% of the unnatural base pairs survived in the amplified DNA.

Using this genetic alphabet expansion system, we developed the generation method of high-affinity Ds-containing DNA aptamers that specifically bind to target proteins or cells. We found that only two or three Ds bases in the aptamers greatly affected the tight binding to target proteins. We are now applying this aptamer technology to developing diagnostic and therapeutic agents as an alternative to antibody technology.

Title: Frustrated Lewis Pairs Catalyzed Metal-Free Hydrogenations and Hydrosilylations
Speaker:Professor Du Haifeng
Date:2nd March 2017
Time:2.00pm to 3.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Steve Zhou
Abstract:

The recently emerging chemistry of frustrated Lewis pairs (FLPs) provides a powerful approach for meal-free hydrogenation and hydrosilylation. Great progress has been achieved in this field. However, highly effective FLP catalysts and highly enantioselective reactions are still very limited. One of the most important point is how to access the sensible borane Lewis acids efficiently. We developed a novel strategy for the development of borane catalysts by the in situ hydroboration of alkenes or alkyns with Piers’ borane HB(C6F5)2. Highly stereoselective and/or enantioselective hydrogenations and hydrosilylations have been achieved. Moreover, a novel FLP mimic of chiral tert-butylsulfinamide and HB(C6F5)2 have been developed for the transfer-hydrogenation.

Title: New Catalytic and Chiroptical Functions of Chirality-Swichable Helical Macromolecule PQX
Speaker:Professor Michinori Suginome
Date:2nd March 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Atsushi Goto
Title: Sulfur Atom Transfer (SAT) Reaction
Speaker:Professor Jiang Xuefeng
Date:1st March 2017
Time:3.00pm to 4.00pm  
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Steve Zhou
Abstract:

The introduction of sulfur atom into target molecule is an important area in organic synthesis, particularly in the synthesis of pharmaceuticals and organic materials. Our group focus on sulfurating reagent development and their methodologies for sulfur containing functional molecule construction from inorganic sulfur salts to organic sulfides. Applying this strategy, diverse of C-S, C=S, and S-S bond was established in natural products and pharmaceuticals. Inspired through O-O fomation, a set of novel S-S reagents are systematically established to introduce S-S in different demand straightforwardly. Based on ligand controlled sulfuration, divergent natural product synthesis were successfully achieved.

Title: Phosphorus Ligands-Enabled Synthesis & Catalysis
Speaker:Professor Tang Wenjun
Date:1st March 2017
Time:2.00pm to 3.00pm  
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Steve Zhou
Abstract:

The talk will be focused on the design and development of a series of practical and efficient P-chiral phosphorus ligands on the basis of a 2,3- dihydrobenzo[d][1,3]oxaphosphole motif. Their distinct structural features offers unique reactivities and selectivities in a number of transitionmetal-catalyzed reactions, providing efficient syntheses to many challenging structures such as chiral amines, chiral biaryls, chiral diaryl alkyl tertiary alcohols, chiral tertiary boronic esters, and chiral all-carbon quaternary stereocenters. These synthetic methods have resulted in green synthesis of several chiral natural products and drugs.

References a) Huang, L.; Zhu, J.; Jiao, G.; Wang, Z.; Yu, X.; Deng, W.-P.;* Tang, W.* Angew. Chem., Int. Ed. 2016, 55, 4527. b) Hu, N.; Li, K.; Wang, Z.; Tang, W. Angew. Chem., Int. Ed. 2016, 55, 5044. c) Hu, N.; Zhao, G.; Zhang, Y.; Liu, X.; Li, G.; Tang, W.* J. Am. Chem. Soc. 2015, 137, 6746. d) Du, K.; Guo, P.; Chen, Y.; Cao, Z.; Tang, W* Angew. Chem., Int. Ed. 2015, 54, 3033. e) Fu, W.; Nie, M.; Wang, A.; Tang, W* Angew. Chem., Int. Ed. 2015, 54, 2520. f) Li, C.; Chen, T.; Xiao, G.; Li, B.; Tang, W* Angew. Chem., Int. Ed. 2015, 54, 3792

Title: ATTOSECOND PHYSICS FOR BIOMEDICINE Field-resolved vibrational molecular spectroscopy for early cancer detection
Speaker:Professor Ferenc Krausz (together with Dr. Mihaela Zigman)
Date:27th February 2017 
Time:11.00am to 12.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Loh Zhi Heng 
Abstract:

Attosecond metrology now allows sampling of the electric field of light with a robust solid-state devices and powerful few-cycle laser technology, opening the door for complete characterization of classical fields all the way from the far infrared to the vacuum ultraviolet. These fields, with accurately measured temporal evolution, serve as a unique probe of the dynamic response of matter. Field-resolved spectroscopy will access (valence) electronic as well as nuclear motions in all forms of matter and constitutes a generalization of pump-probe approaches. Its implementation with a solid-state instrumentation opens the door for real-world applications, such as early cancer detection by measuring miniscule changes of the molecular composition of blood (liquid biopsy) via field-resolved vibrational molecular fingerprinting.

Title: Reactions and Molecular Functions Featuring Elements-based Characteristics
Speaker:Professor Ryo Takita
Date:24th February 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Shunsuke Chiba
Abstract:

We concentrate on the development of reactions and functions featuring elements-based characteristics, in particular, based on main group elements or non-toxic, abundant metal elements. Among our recent research, the development of some borylation reactions and direct hydroxylation/amination of aromatic compounds, and cross-coupling reaction and molecular functions based on monocarba-closododecaborate ([CB11H12]–, “C1-carborane anion”) will be discussed.

Title: On Discovery in Catalysis
Speaker:Professor Frank Glorius
Date:21st February 2017
Time:11.00am to 12.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Robin Chi 
Abstract:

Catalysis is a key technology of our modern societies, since it allows for increased levels of selectivity and efficacy of chemical transformations. While significant progress can be made by rational design or engineered step-by-step improvements, many pressing challenges in the field require the discovery of new and formerly unexpected results. Arguably, the question “How to discover?” is at the heart of the scientific process. In this talk, strategies and discoveries from the Glorius group will be discussed. Topics will involve the use of N-heterocyclic carbenes in different fields of catalysis1 and also photocatalysis. 2

1) Hopkinson, M. N.; Richter, C.; Schedler, M.; Glorius, F., Nature 2014, 510, 485. 2) Hopkinson, M. N.; Gomez-Suarez, A.; Teders, M.; Sahoo, B.; Glorius, F. Angew. Chem. Int. Ed. 2016, 55, 4361.

Title: ELECTRONS IN REAL TIME Tracking and controlling motions at the picometer-attosecond scale
Speaker:Professor Ferenc Krausz
Date:20th February 2017
Time:4.00pm to 5.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Loh Zhi Heng
Abstract:

Born around the turn of the new millennium, attosecond metrology opened the door for observing atomic-scale electron dynamics in real time. The novel technology is more than an extension of femtosecond technology to a briefer time scale. It is based – for the first time – on the electric force of light for controlling and tracking microscopic motions. The controlled light force is now providing access to electronic motions at the picometer-attosecond scale but reconstructing them in complex systems calls for yet another revolution in ultrafast science.

Title: Efficient ligand platforms from our group for enantioselective catalysis
Speaker:Professor Anton Vidal
Date:20th February 2017
Time:3.00pm to 4.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Shunsuke Chiba
Abstract:

Our research interests encompass the design of efficient enantioselective catalysts for transformations of interest, and the study of their use to prepare enantiomerically enriched products of biological, or pharmaceutical relevance. Crucial aspects of this work include modular design of the catalysts; use of versatile synthetic procedures (organic and inorganic transformations, or supramolecular processes); incorporation of regulation mechanisms for their active-site geometry; and computational study of their catalytic cycles (through collaborations). The application of our ligands in rhodium-mediated hydrogenative desymmetrizations of achiral dienes, rhodium-mediated hydrogenative kinetic resolutions of vinyl sulfoxides and supramolecularly regulated hydroformylation and metal carbene C-H insertion reactions, among other transformations, will be discussed.

Title: Enantioselective Photo-Organocatalysis: Making Chiral Molecules with Light
Speaker:Professor Paolo Melchiorre
Date:20th February 2017
Time:2.00pm to 3.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Robin Chi
Abstract:

Light-driven processes considerably enrich the modern synthetic repertoire, offering a potent way to build complex organic frameworks. 1 In contrast, it is difficult to develop enantioselective catalytic photoreactions that can create chiral molecules with a well-defined threedimensional arrangement. 2 Recently, our research laboratories3 has started a program aimed at translating the effective tools governing the success of ground state asymmetric organocatalysis into the realm of photochemical reactivity, exploiting the potential of key organocatalytic intermediates to directly participate in the photoexcitation of substrates. At the same time, the chiral organocatalyst can ensure effective stereochemical control. This single catalyst system, where stereoinduction and photoactivation merge in a sole organocatalyst, can serve for developing novel enantioselective photoreactions. The new synthetic possibilities, opened up by the application of organocatalysis within photochemical and radical patterns, will be discussed. 4

1. Shultz, D. M.; Yoon, T. P. Science 2014, 343, 1239176. 2. Brimioulle, R.; Lenhart, D.; Maturi, M. M.; Bach, T. Angew. Chem., Int. Ed. 2015, 54, 3872–3890. 3. (a) Arceo, E.; Jurberg, I. D.; Álvarez-Fernández, A.; Melchiorre, P. Nature Chem. 2013, 5, 750–756. (b) Woźniak, Ł.; Murphy, J. J.; Melchiorre, P. J. Am. Chem. Soc. 2015, 137, 5678–5681. (c) Murphy, J. J.; Bastida, D.; Paria, S.; Fagnoni, M.; Melchiorre, P. Nature 2016, 532, 218–222. 4. Research supported by the ICIQ Foundation, MINECO (project CTQ2013-45938-P, SEV-2013-0319), the AGAUR (2014 SGR 1059), and the European Research Council (ERC 681840 - CATA-LUX)

Title: Organic Synthesis in CRO & CMO Industry
Speaker:Dr. Ma Rujian
Date:8th February 2017
Time:3.00pm to 4.30pm   
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Dr Sumod Pullarkat
Title: Chemical Synthesis of Complex Natural Glycosides of Biological Significance
Speaker:Professor Yu Biao
Date:7th February 2017
Time:4.30pm to 6.00pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Liu Xuewei
Abstract:

Many complex natural glycosides possess remarkable biological properties, therefore have attracted great attentions in chemical synthesis in order to understand their structure-activity relationships and the mechanisms of action. Focusing on the construction of the glycosidic linkages between the aglycon and the saccharides, I shall discuss the general synthetic strategies[1] and the glycosylation methods.[2] Highlighted are the gold(I)-catalyzed glycosylation protocol with ortho-alkynylbenzoates as donors[3] and its application in the synthesis of the biologically significant steroid glycosides, namely gordonoside F[4] and periploside A.[5]

Reference (1) B. Yu, J. Sun, X. Yang, Acc. Chem. Res. 2012, 45, 1227. (2) Y. Yang, X. Zhang, B. Yu, Nat. Prod. Rep. 2015, 32, 1331. (3) Y. Tang, J. Li, Y. Zhu, Y. Li, B. Yu, J. Am. Chem. Soc. 2013, 135, 18396. (4) S. Zhang, Y. Ma, J. Ma, B. Yu, X. Xie, Proc. Natl. Acad. Sci. USA 2014, 111, 14571. (5) X. Zhang, Y. Zhou, J. Zuo, B. Yu, Nature Commun. 2015, 6: 5879.

Title: Vibrational Anharmonicity and IR Spetra of Protonated Clusters
Speaker:Professor Kuo Jer-Lai
Date:6th February 2017
Time:11.00am to 12.30pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Tan Howe Siang
Abstract:

Structure of hydrate proton is typically classified into Eigen (H3O+) and Zundel (H5O2+) forms. While this is a textbook knowledge, it remains very challenging to keep track of their vibrational signatures owing to the strong vibrational coupling. We have developed several computational scheme to reveal the vibrational couplings (from strong to weak) with the hope to link vibrational spectra and the structure of these clusters. Gas-phase ionic spectra collected over the last two decades have provided plenty of experimental vibrational spectra that allow us to examine the vibrational motion of proton in H-bonded cations. In this talk, we will present our recent systematic theoretical studies both different types of Zundel1,2 and H3O+ under different solvation environments3,4. Our theoretical studies engage ab initio treatment on a selected set of quantum degrees of freedom and treat their vibrational anharmonicity/coupling explicitly. If time permits, we will also access the performance of a few approximate treatments on vibrational coupling/anharmonicity to treat larger molecular systems5.

[1] J.A. Tan and J.-L. Kuo. J. Phys. Chem. A., 119, 11320 (2015) [2] J.A. Tan and J.-L. Kuo. Phys. Chem. Chem. Phys., 18, 14531 (2016) [3] J-W Li, M. Morita, T. Takahashi, and J-L Kuo, J. Phys. Chem. A, 119, 10887 (2015) [4] J. Tan, J-W Li, C-c Chiu, H.Huynh, H-Y Liao, and J-L Kuo, Phys. Chem. Chem. Phys., 18, 30721 (2016) [5] K-L Ho, L-Y Lee, M. Katada, A. Fujii, and J-L Kuo, Phys. Chem. Chem. Phys., 18, 30498 (2016)

Title: Organometallic anticancer drugs: example of the ferrocifen family
Speaker:Professor Gérard Jaouen
Date:25th January 2017
Time:1.30pm to 3.00pm  
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Associate Professor Leong Weng Kee
Abstract:

Owing to the poor outcomes seen in several types of cancers (e.g. epithelial ovarian cancer, EOC) the search for new active principles outside the established avenues is a burning current concern. In our search for innovative organometallics species able to overcome drug resistance to proapoptotic stimuli we have discovered that the remarkable ferrocifen family bearing a redox motif [ferrocenyl-ene-phenol] selectively activated on cancer cells, and therefore revealing their redox environment. Biologically these species can operate via mechanisms related to both apoptosis and senescence depending on several parmeters. This multitargeting property can inhibit resistance. Among the usable organometallic complexes, iron derivatives occupy a privileged position associated with the particular nature of ferrocene, which is a non-toxic, compact and stable aromatic metallocene with redox properties and a bioisostere of benzene.

It is important to elucidate the chemical behavior of the key metabolites generated oxidatively from the metallocifens in relation to their antitiproliferative effects. This study produced multiple surprises and will be discussed in depth. Interestingly metallocifen mechanisms depend on several parameters such as the nature of the metal, the shape of the carbon skeleton and the kind of substituents. All these effects will be shown and related to antiproliferative behaviors.

Title: Exploring Carbon Neutral Methods for the Interconversion of Ammonia with its Elements
Speaker:Professor Paul Chirik
Date:18th January 2017
Time:5.00pm to 6.30pm 
Venue:SPMS Lecture Theatre 5
Host:Assistant Professor Soo Han Sen 
Abstract:

The synthesis of ammonia from its elements, N2 and H2 , and the reverse reaction, the oxidation of NH3 to dinitrogen and dihydrogen are chemical transformations that are key for carbon neutrality. The stoic Haber-Basch industrial ammonia synthesis relies on methane-derived hydrogen, generates considerable CO2 pollution and inspires the search for alternative methods compatible with renewable H2 . Our research group is exploring proton coupled electron transfer (PCET) methods as a pathway for N-H bond formation and scission. Measurement of N-H bond dissociation free energies (BDFEs) of coordinated nitrogen ligands (amides, imides, hydrazides, and ammonia) accompany our approach and guides rational design of transition metal complexes and optimization of ligands to attenuate redox potentials and N-H acidity.

Concurrent with this approach, we are determining the BDFEs of bis(cyclopentadienyl) titanium and zirconium amides and applying PCET from Cr and Rh hydrides to the metal amides to generate free ammonia. The thermodynamic viability of PCET can be predicted and attenuated through an understanding of both the hydrogen atom donor and the nitrogen acceptor using thermochemical square schemes (see J. Am. Chem. Soc. 2016, 138, 13379). Notably, the Cr and Rh hydrides are regenerated under an atmosphere of hydrogen enabling the catalytic hydrogenolysis of metal amides, imides, and hydrazides using PCET. Redox active ligands have also been used to modify the redox potentials of Ti, V and Mo complexes and examples of N-N bond cleavage and N-H bond formation has been observed.

The reverse reaction, liberation of H2 from ammonia is also a challenge in contemporary energy science. This reaction has received considerable less attention that N2 hydrogenation and most organometallic approaches have relied on oxidative addition to break the N-H bond and do not ultimately result in H2 production. Our laboratory has recently discovered “bond weakening by coordination” whereby coordination of NH3 to a transition metal significantly reduces the N-H bond dissociation free energy and enables H2 formation by proton coupled electron transfer (see Science 2016, 354, 730). The mechanism of H2 synthesis and the factors that result in this unusual effect will be the focus of my lecture.

Title: Catalysis with Earth Abundant Metals
Speaker:Professor Paul Chirik
Date:18th January 2017
Time:10.30am to 12.00pm
Venue:SPMS Lecture Theatre 5
Host:Assistant Professor Soo Han Sen 
Abstract:

Transition metal catalysis has revolutionized modern society by enabling new chemical transformations with unprecedented activity and control over selectivity. Applications range from new silicone materials to transforming hydrocarbons into fuels to building blocks for pharmaceuticals. Our laboratory has been actively engaged in developing catalysts based on earth abundant elements rather than more traditionally deployed precious metals that are some of the least available elements in the Earth’s crust. The inspirations for this chemistry extend beyond catalyst cost; ultimately we aim to discover new reactivity that exploits the unique electronic structures of first row transition metals. My lecture will combine applications developed in combination with industrial collaborators. Earth abundant catalysts for commercial silicone production (Science 2012, 335, 567, ACS Catalysis 2016, 6, 4105), asymmetric alkene hydrogenation (Science 2013, 342, 1054, J. Am. Chem. Soc. 2016, 3562), C-H functionalization (J. Am. Chem. Soc. 2014, 136, 4133; 2016, 138, 766) and radiolabeling of pharmaceuticals (Nature 2016, 529, 195) have been developed. More recently we have been focused on the discovery of new catalytic reactions for the valorization of simple alkenes – those that are now overabundant due to the development of vast natural gas reserves. An iron-catalyzed method for the diastereo- and regioselective intermolecular [2+2] cycloaddition of commodity alkenes has been discovered (Science 2015, 349, 960). Through continued ligand evolution and understanding of electronic structure, we have discovered base metal catalysts that promote chemistry unknown with established precious metal variants. The mechanisms of the various catalytic transformations, the importance of electronic structure controlled through ligand manipulation and strategies for imparting air stability will be a highlighted throughout.

Title: Merging of Chemistry and Biology: In Search of Molecules with Translational Function
Speaker:Professor Kim Janda
Date:12th January 2017
Time:11.00am to 12.30pm 
Venue:SPMS MAS Executive Classroom 1
Host:Assistant Professor Steve Zhou 
Abstract:

This lecture will illustrate the opportunities that lie at the interface of biological chemistry by describing a series of examples, including developing vaccines for treating heroin abuse, cell-to-cell communication within bacteria and how some of these quorum-sensing molecules display a symbiotic relationship to cancer immunosurveillance as it relates to TRAIL’s apoptotic pathway.

Title: Practical Direct Electrophilic Amination of Olefins and Aromatic Systems
Speaker:Professor László Kürti
Date:9th January 2017
Time:12.00pm to 1.30pm 
Venue:SPMS Research & Graduate Studies Office Conference Room
Host:Professor Tan Choon Hong
Abstract:

Amines and their derivatives are ubiquitous substances since they make up the overwhelming majority of drug molecules, agrochemicals as well as many compounds that are produced by plants and living organisms (i.e., natural products). Aromatic amines appear as substructures in more than one third of drug candidates while aziridines, in which the nitrogen atom is bridged between two carbon atoms, are high-reactive and versatile building blocks for a large variety of functionalized amines. Not surprisingly, organic chemists spend a considerable amount of their time with the synthesis and late-stage functionalization of amines that serve as key chemical building blocks for the preparation of biologically active compounds, especially in medicinal chemistry. There is an urgent need for the development of novel carbon-nitrogen bondforming methods and reagents that expand the toolbox of synthetic organic chemists and enable the environmentally friendly construction of complex molecular structures using the fewest number of chemical steps and generating the least amount waste. A highly attractive, but currently underdeveloped, approach is the utilization of weak bonds as a driving force to achieve the rapid formation of much stronger bonds under mild conditions. The Kürti lab has been exploring several fundamentally new strategies for the transition-metalfree direct: (i) primary amination of arylmetals such as aryl Grignard reagents and arylboronic acids; (ii) intramolecular C(sp2)-H amination of arenes; (iii) double arylation of a suitable nitrogen linchpin reagents to afford N,N-diarylamines. We have also discovered, in collaboration with the Falck (UTSW) and Ess labs (BYU), the Rh-catalyzed direct N-H/N-alkyl aziridination of olefins as well as the primary (-NH2) and NH-alkyl amination of arenes, transformations that eluded synthetic chemists for decades. These methods have one common feature: a weak N-O bond is cleaved in order to form a stronger C-N bond. In-depth experimental and computational studies have already identified the critical factors required for efficient olefin Nhand N-alkyl aziridination as well as direct arene primary amination and led to the development of practical and chemoselective aminating agents.

References (1) Kürti, László. “Streamlining Amine Synthesis” – A Perspective. SCIENCE 2015, Vol 348, no 6237, p864-865 (DOI:10.1126/science.aab2812). (2) Jat, Jawahar L; Paudyal, Mahesh P.; Gao, Hongyin; Xu, Qing-Long; Yousufuddin, Muhammed.; Devarajan, Deepa; Ess, Daniel H*.; Kürti, László and Falck, J.R. “Direct and Stereospecific Synthesis of Unprotected N-H and N-Me Aziridines from Olefins.” SCIENCE 2014, Vol 343, no 6166, p 61-65. (3) Paudyal, Mahesh P., Adebesin, Adeniyi M., Burt, Scott R., Daniel H. Ess, Ma, Zhiwei, Kürti, László and John R. Falck. ”Dirhodium-catalyzed C-H arene amination using hydroxylamines.” SCIENCE 2016, Vol 353, no 6304, p 1144-1147.