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Professor Ben Feringa - 2016 Nobel Prize in Chemistry

Title: To be defined

Abstract:

Professor Ying-Yeung YEUNG

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Title: Organocatalytic ortho-Selective Halogenation Reactions

Abstract: Electrophilic halogenation reactions are an important class of organic transformations. One of the focuses in our research group is on the development of novel organocatalytic halogenation reactions using N-halosuccinimides, which are inexpensive and easy-to-handle halogen sources [1]. For example, we have developed ortho-selective mono-halogenation of arenes using ammonium salts as the catalysts [2]. In this lecture, we will present a facile strategy in the preparation of chiral bisphenols (BPOLs) through the desymmetrizing asymmetric ortho-halogenation [3].

 

[1] (a) Chen, F.; Tan, C. K.; Yeung, Y.-Y. J. Am. Chem. Soc. 2013, 135, 1232. (b) Ke, Z.; Tan, C. K.; Chen, F.; Yeung, Y.-Y. J. Am. Chem. Soc. 2014, 136, 5627. (c) Cheng, Y. A.; Yu, W. Z.; Yeung, Y.-Y. Angew. Chem. Int. Ed. 2015, 54, 12102. (d) Chan, Y.-C.; Yeung, Y.-Y. Angew. Chem. Int. Ed. 2018, 57, 3483.

[2] (a) Xiong, X.; Yeung, Y.-Y. Angew. Chem. Int. Ed. 2016, 55, 16101. (b) Xiong, X.; Yeung, Y.-Y. ACS Catal. 2018, 8, 4033.
[3] Xiong, X.; Zheng, T.; Wang, X.; Tse, Y.-L. S.; Yeung, Y.-Y. Chem 2020, DOI: 10.1016/j.chempr.2020.01.009.

Professor Ruben Martin

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Title: Ni-catalyzed functionalization of remote sp3 C–H bonds

 

Abstract: In recent years, chemists have been challenged to design new catalytic methodologies for converting (un)saturated hydrocarbons into value-added products by means of catalytic sp3 C-H functionalization. However, the ability to enable catalytic C-C bond-formation from a simple hydrocarbon is not particularly straightforward, as sp3 C-H bonds are less acidic and lack proximal empty low-energy or filled high-energy orbitals that interact with the d orbitals of the transition metal. Indeed, saturated hydrocarbons rank amongst the least reactive molecules, and their inertness is somewhat reflected by the forcing conditions that are required in the very few alkane transformations performed in industry, for example the cracking or reforming processes in oil refineries using heterogeneous catalysts operating at temperatures of approximately 400 to 600 ºC. Additionally, we should take into consideration site-selectivity principles due to the presence of multiple, yet similar, sp3 C-H bonds within the alkyl side chain. Recently, our group has developed a series of Ni-catalyzed reactions that enable the functionalization of remote sp3 C-H bonds in both saturated and unsaturated hydrocarbons via a formal dynamic displacement of the catalyst throughout the alkyl side-chain. These transformations are characterized by its simplicity, generality and modularity, thus increasing our ever-growing arsenal for converting simple precursors into added-value chemicals.

Professor Ang Li

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Title: Total Synthesis of Polycyclic Natural Products

 

Abstract: A series of syntheses of polycyclic natural products (in particular alkaloids) will be presented in this lecture. Septedine is a hetidine type C20-diterpenoid alkaloid bearing an oxygenated heptacyclic scaffold. We have accomplished the total synthesis of septedine. A functionalized tricyclic intermediate was prepared with excellent enantiopurity by using Carreira polyene cyclization. An unusual anionic Diels–Alder reaction was responsible for the construction of the bicyclo[2.2.2]octane. Sanford Csp3–H oxidation was exploited to install the secondary hydroxy group of. The oxazolidinopiperidine was assembled by selective reductive amination and spontaneous N,O-ketalization at a final stage. The total synthesis of arcutinidine, arcutinine, and arcutine, three arcutine-type C20-diterpenoid alkaloids, has also been achieved. A pentacyclic intermediate was rapidly assembled by using two Diels−Alder reactions. We developed a cascade sequence of Prins cyclization and Wagner−Meerwein rearrangement to construct the core of arcutinidine, which was then elaborated into an oxygenated pentacycle through a scalable route. Chemoselective reductive amination followed by spontaneous imine formation furnished the pyrroline motif in the final stage. We clarified the S configuration of the α-carbon of the acyl group within arcutine through chemical synthesis and crystallographic analysis.

Professor Tomislav Rovis

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Title: Controlling Catalysis with Visible Light

Abstract: Visible light is an abundant energy source that can also be delivered on demand. Harnessing the energy in visible light has recently been accomplished through the use of photoredox catalysis, which can generate radical intermediates by an oxidation or reduction step to initiate a bond formation followed by a return of the electron or hole to close the catalytic cycle. We have been engaged in expanding the versatility of visible light photoredox catalysis and have uncovered strategies to effect C-H activation in unactivated positions of alkanes as well as controlling catalysis spatially and temporally. Reaction development, mechanistic investigations and synthetic applications will be the subject of this lecture.
 

Professor John Bower

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Title: Catalytic Chirality Generation: New Strategies for Organic Synthesis

Abstract: Our group develops new catalysis platforms that enable the efficient generation of chiral building blocks and heterocyclic scaffolds. Current priority areas include: (i) the development of catalytic C-C bond activation processes and associated cycloadditions [1], (ii) the development of aza-Heck reactions [2], and (iii) the development of enantioselective alkene hydroarylation reactions [3]. Selected recent highlights will be presented. 

 

Representative publications:

[1] Wang, G.-W.; Bower, J. F. J. Am. Chem. Soc. 2018, 140, 2743.

[2] Ma, X.; Hazelden, I. R.; Langer, T.; Munday, R. H.; Bower, J. F. J. Am. Chem. Soc. 2019, 141, 3356.

[3] Grélaud, S.; Cooper, P.; Feron, L. J.; Bower, J. F. J. Am. Chem. Soc. 2018, 140, 9351.

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Professor Debabrata Maiti

Title: Designing of templates to reach the distal C–H bond
 

Abstract: Mimicking the nature has always been a coveted target for scientific communinities. A precise understanding has emerged as to how enzymes accomplish the chemical transformations. Enzymes catalyze inert C-H bond functionalization in a regio- and stereoselective manner using metal-active site. Inspired by the nature, we have developed catalytic methods to functionalize carbon–hydrogen (C–H) bonds which provides significant economic and environmental benefits over traditional synthetic methods. Applicability of our strategies towards synthesis of various complex molecules will be discussed.
 

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Professor Jared T. Shaw

Title: Enantioselective C–H Insertion Reactions of Donor/Donor Carbenes for the Synthesis of Complex Natural Products

Abstract: Rhodium carbenes lacking electron withdrawing groups, or “donor/donor” carbenes, participate in a wide variety of selective reactions. Due to the reduced electrophilicity, these reactive intermediates exhibit remarkable functional group tolerance, enabling access to uniquely complex organic molecules. The development of new methods and their application to the synthesis of a series of complex heterocycles, including several natural products, will be described.

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Professor Pauline Chiu

Title: Cycloadditions for Assembling Cycloheptanoids Towards the Synthesis of Natural ProductsTo be defined

Abstract: To address the synthesis of natural products having a cycloheptanoid framework, we have been studying (4+3) and (5+2) cycloadditions to provide functionalized seven-membered carbocycles, and in enantiomerically enriched forms.  In this lecture, we will report our results, and our attempts to apply them to the synthesis of various natural products.

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Professor Diego Alves

Title: Synthesis of highly functionalized 1,2,3-triazoles systems through copper- or organocatalysis protocols

Abstract: This presentation will provide a comprehensive overview of reported methods particularly copper- and organocatalyzed reactions - for the regioselective syntheses of high functionalized 1,2,3-triazoles systems. These chemical entities are prevalent cores in biologically active compounds and functional materials. In view of their unique properties, substantial efforts have been paid for the design and development of practical approaches for the synthesis of these scaffolds.

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Professor Annaliese Franz

Title: Organosilicon Chemistry for Enantioselective Synthesis, Catalyst Design and Medicinal Chemistry

Abstract: The successful development of new synthetic methods and catalysts is important for the discovery and production of chiral organic molecules and materials. This talk will highlight several examples of organosilicon chemistry that provide rich opportunities and applications for methodology, mechanism and novel synthetic targets. First, the development of enantioselective synthesis and molecular recognition components involved to access chiral-at-silicon molecules will be presented with applications for the design of new catalyst systems based on siloxy compounds.  Second, the unique reactivity of allylsilane and allenylsilane nucleophiles will be featured to demonstrate opportunities to develop efficient methods for the enantioselective synthesis of complex molecules such as spirooxindoles, as well as interesting opportunities to explore mechanistic features of annulation reactions and Lewis acid-catalyzed reactions. Finally, examples for the synthesis of novel organosilicon targets with medicinal applications will be presented. For all studies, results of structural, mechanistic, kinetics and molecular binding studies will be included to provide insight for catalyst activity, design and synthetic applications.

Professor Elisa S. Orth

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Title: Imidazoles: promiscuous or versatile towards organophosphates?

 

Abstract: Is the broad mechanistic versatility of Imidazoles towards organophosphates, that has inspired many catalysts, beneficial or a threateningly promiscuity? We have been working on unravelling this puzzle and show how varying the nature of the organophosphate can lead to N-phosphorylation or unusual N-alkylation. Also, the structure of imidazole derivatives are evaluated, which also show an interesting trend. Should this add to the known versatility of Imidazole or can it be considered an unsought promiscuity? A concise understanding of the mechanism underlying organophosphates is imperative for effectively applying in real destruction or monitoring systems of agrochemicals. Preferably, one seeks less toxic products and no side reactions. Moreover, we show that one monitoring system may not apply to various toxic agrochemicals, since their structure can shift the mechanism, hence lead to different products and suppress important signals or give false positives.

Professor Daniel Werz

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Title: Carbopalladation Cascades – Not only syn, but also anti


Abstract: A characteristic feature of carbopalladation reactions is the syn-attack of the organopalladium species LnX[Pd]-R on the reacting π-system [1]. Such a step results in compounds bearing Pd and R on the same side of the originating alkene moiety. Embedded into longer domino sequences complex structures are efficiently obtained by a repetition of this syn-carbopalladation step. In this way, linear oligoynes were cyclized in a dumbbell-mode and led to benzene-type structures or higher oligoenes [1]. We exploited this chemistry to synthesize not only chromans, isochromans [2] and dibenzopentafulvalenes [3], but also to access the most truncated π-helicenes which only consist of a Z,Z,Z,..-oligoene chain that is fixed in an all s-cis arrangement [4]. All these domino processes are based on a syn-carbopalladation cascade. However, a carbopalladation cascade involving formal anti-carbopalladation steps opens new avenues to create compounds with tetrasubstituted double bonds. Such a process was realized, and mechanistically and computationally investigated. The synthetic potential was demonstrated for the preparation of various oligocyclic frameworks (including natural products) by making use of a variety of different terminating processes [5].

 

[1] E. Negishi, G. Wang, G. Zhu, Top. Organomet. Chem. 2006, 19, 1-48; [2] M. Leibeling, D. C. Koester, M. Pawliczek, S. C. Schild, D. B. Werz, Nat. Chem. Biol. 2010, 6, 199; [3] J. Wallbaum, R. Neufeld, D. Stalke, D. B. Werz, Angew. Chem. Int. Ed. 2013, 52, 13243; [4]  B. Milde, M. Leibeling, M. Pawliczek, J. Grunenberg, P. G. Jones, D. B. Werz, Angew. Chem. Int. Ed. 2015, 54, 1331; [5] a) M. Pawliczek, T. F. Schneider, C. Maaß, D. Stalke, D. B. Werz, Angew. Chem. Int. Ed. 2015, 54, 4119. b) M. Pawliczek, B. Milde, P. G. Jones, D. B. Werz, Chem. Eur. J. 2015, 21, 12303; c) A. Düfert, D. B. Werz, Chem. Eur. J. 2016, 22, 16718; d) B. Milde, M. Pawliczek, P. G. Jones, D. B. Werz, Org. Lett. 2017, 19, 1914.

Professor Cristiano Raminelli

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Title: Benzyne Chemistry: Synthetic Methods and Total Syntheses


Abstract: The benzyne chemistry has found applications in organic chemistry, including total syntheses of natural products and preparations of functional materials. In this context, 2-(trimethylsilyl)aryl trifluoromethanesulfonates can be considered an important alternative for the generation of benzyne and derivatives, enlarging the scope of benzyne chemistry applications in preparative organic chemistry. Accordingly, in our lecture we intend to present useful synthetic methods for the preparation of heterocyclic compounds and concise approaches to the total syntheses of natural products and bioactive compounds, involving the generation of benzyne and derivatives via fluoride-induced reactions under mild conditions.

Professor María Laura Uhrig

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Title: From thiosugars and thiodisaccharides to supramolecular multivalent ligands


Abstract: Thioglycosides and thiodisaccharides represent a synthetic challenge for carbohydrate chemists due to their increasing importance in the Glycobiology field. In these compounds, the anomeric oxygen has been replaced by a sulfur atom, and so, they are considered carbohydrate mimetics with great potential as enzyme inhibitors or new ligands for lectins, given that this replacement does not interfere with recognition events. Moreover, this structural feature makes them more resistant towards enzymatic and acidic hydrolysis. Therefore, the development of new synthetic methods to obtain thiosugars and their use as building blocks for the synthesis of new carbohydrate-derived compounds have been an active research field over the years. In our laboratory, we are interested in developing multivalent systems with high affinity for lectins, constructed from glycomimetics such as thiosugars and thiodisaccharides. Thus, after exploring a range of covalently-constructed multivalent structures, we undertook the study of self-assembled multivalent systems produced from amphiphilic compounds. In all cases, we have incorporated thiosugars such as 1-thiolactose, β-S-N-acetylglucosamine and even thiodisaccharides as recognition elements, which were, at the same time, the polar moiety of the amphihile. Pyrene and resorcinarene systems, as well as long chain diacyl-derived tartaric residues, have been used as hydrophobic residues. Thus, in this presentation I will refer to our latest results on the synthesis and characterization of supramolecular multivalent ligands for lectins. It will include the synthetic results regarding the construction of GlcNAc-thiodisaccharides, and also our experience on a variety of self-assembled and micellar systems, including gels, which have shown high affinity for model lectins.

Professor Michael S. Sherburn

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Title: To be defined


Abstract:

Professor Ross Denton

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Title: Organocatalytic Alcohol Activation


Abstract: Nucleophilic substitution reactions are fundamental transformations in organic synthesis because they allow readily available alcohols to be converted into a wide variety of functional groups with predictable inversion of stereochemistry. However, they are inherently wasteful since alcohol activation is necessary and takes place at the expense of a stoichiometric reagent. The lecture will describe the design and development of organocatalytic platforms for catalytic nucleophilic substitution reactions of alcohols and epoxides as well as applications in natural product and active pharmaceutical ingredient synthesis.

Professor László Kürti

Title: Electrophilic Nitrogen-Transfer Processes

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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) [1]. Aromatic amines appear as substructures in more than one third of drug candidates. 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 bond-forming 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. Given this background, the Kürti group actively pursues catalytic C-N bond-forming strategies and processes (i.e., novel modes of nitrogen-transfer) in which the nitrogen-containing group is introduced directly in an unprotected form (i.e., NH2, NH-alkyl and NH-aryl) [2-6]. Despite the recent substantial research effort focused in this area, progress has been limited. This is in part due to a general lack of development of a wide variety of electrophilic aminating agents and catalysts with finely-tuned electronic and steric properties to provide optimal reactivity with a wide range of substrates. The presentation will highlight our latest results on the currently underexplored field of organocatalytic nitrogen-transfers that allow the direct NH-aziridination of isolated/unactivated C=C bonds with high chemoselectivity. These type of processes are intriguing both from a mechanistic and sustainability point of view.

 

[1] Kürti, László. “Streamlining Amine Synthesis” – A Perspective. SCIENCE 2015, Vol 348, no 6237, p864-865.
[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] Gao, Hongyin; Zhou, Zhe; Kwon, Doo-Hyun; Coombs, James; Jones, Steven; Behnke, Nicole E.; Ess, Daniel H. and Kürti, László. “Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds.” Nature Chemistry, 2017.
[4] Zhou, Zhe; Ma, Zhiwei; Behnke, Nicole Erin; Gao, Hongyin and Kürti, László. “Non-Deprotonative Primary and Secondary Amination of (Hetero)Arylmetals.” J. Am. Chem. Soc. 2017, 139, 115-118.
[5] Padmanabha V. Kattamuri, Jun Yin, Surached Siriwongsup, Doo-Hyun Kwon, Daniel H. Ess*, Qun Li, Guigen Li*,, Muhammed Yousufuddin, Paul F. Richardson, Scott C. Sutton and Kürti, László.* “Practical Singly and Doubly Electrophilic Aminating Agents: A New, More Sustainable Platform for Carbon-Nitrogen Bond-Formation.” J. Am. Chem. Soc. 2017, 139, 11184-11196.
[6] Zhou, Zhe; Cheng Qingqing and Kürti, László. “Aza-Rubottom Oxidation: Synthetic Access to Primary a-Aminoketones.” J. Am. Chem. Soc. 2019, 141, 2242-2246.