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2016.09.20 16:37

[Thu. 22 Sep. 2016] Prof. Anna Lee/Organocatalyzed Asymmetric Reactions

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Speaker Prof. Anna Lee
Date Thursday 22 September 2016
Time 5:00pm
Venue #331, Asan Hall, College of Science

Organocatalyzed Asymmetric Reactions

 

 

The Catalytic Asymmetric Knoevenagel Condensation: The Knoevenagel condensation reaction developed by Emil Knoevenagel in 1896 is a powerful and efficient carbon-carbon bond forming reaction, but also the root of aminocatalysis. Remarkably though, while the Knoevenagel reaction, as the historic basis of all aminocatalyzed processes, has been incorporated into asymmetric organocascades and domino reactions, and even chiral auxiliary derived malonates have been studied, a variation in which the Knoevenagel reaction itself is utilized to establish asymmetry remained elusive. The main problems of the reaction were reactivity and stereoselectivity issues as well as the formation of by-products. The goal of this work was to develop the first enantioselective Knoevenagel condensation reaction using a novel chiral amine catalyst based on a dynamic kinetic resolution (DKR). Various chiral amine catalysts were synthesized, and we found that modified cinchona based amine catalysts provided the desired product in high yield and enantioselectivity.

 

figure.PNG

 

A Cooperative N-Heterocyclic Carbene/Chiral phosphate Catalysis System for Allenolate Annulations: NHC-catalyzed homoenolate additions to various electrophiles represent an enabling class of transformations that have been employed for the construction of complex hetero- and carbocyclic system through unconventional Umpolung reactivity. Recently, our group developed Lewis acid/NHC cooperative catalysis to develope novel transformations. In this study, we have extended the scope of cooperative catalysis by employing chiral phosphoric acids for the first time and this novel cooperative catalysis was applied to the challenging allenolate annulation reaction (Figure 1). A limited number of reports of NHC-catalyzed homoenolate additions involving alkynyl aldehydes have appeared. We have developed a highly efficient asymmetric [3+2] annulation reaction of alkynyl aldehydes withα-ketoesters via NHC/chiral phosphate cooperative catalysis.

 

figure2.PNG

 

 

 

 

References

1. Lee, A.; Michrowska, A.; S.-Mosse, S.; List, B., Angew. Chem. Int. Ed. 2011, 50, 1707.

2. Lee, A.; Reisinger, C.; List, B., Adv. Synth. Catal. 2012, 354, 1701.

3. Lee, A.; Scheidt, K. A., Angew. Chem. Int. Ed. 2014, 53, 7594.

4. Lee, A.; Younai, A. ; Price, C. K. ; Izquierdo, J. ; Mishra, R. K. ; Scheidt, K. A., J. Am. Chem. Soc. 2014,136, 10589.

5. Lee, A.; Scheidt, K. A., Chem. Commun. 2015, 51, 3407.

 

 

Prof. Anna Lee

Myongji University, Department of Chemistry, Yongin, Korea

 

 


List of Articles
No. Subject Speaker Date
Notice Spring semester 2017 Seminar Schedule file - -
33 [Wed. 5 July. 2017] Seminar was canceled! - -
32 [Wed. 28 Dec. 2016] Prof. James Y. Hamilton/Development of a Broad Range of Asymmetric C–C Bond Forming Reactions with a Versatile Iridium Catalyst file Prof. James Y. Hamilton Wednesday 28 December 2016
31 [Thu. 9 Mar. 2017] Prof. Woon Ju Song/Department of Chemistry, Seoul National University, Seoul, Korea Prof. Woon Ju Song Thu. 9 Mar. 2017
30 [Thu. 9 Jun. 2016] Prof. Yong-Young Noh/Development of Printed Large Area Organic Transistors and Integrated Circuits Prof. Yong-Young Noh Thursday 9 June 2016
29 [Thu. 8 Sep. 2016] Prof. Jaeyoung Sung/Stochastic chemical dynamics in living cells and its consequence for the control capacity of living cells over biological functions Prof. Jaeyoung Sung Thursday 8 September 2016
28 [Thu. 8 Jun. 2017] Prof. Won-jin Chung/Department of Chemistry, GIST, Gwangju, Republic of Korea Prof. Won-jin Chung Thu. 8 Jun. 2017
27 [Thu. 6 Oct. 2016] Prof. Young S. Park/Atomistic Molecular Engineering of Polycyclic Aromatic Hydrocarbons Prof. Young S. Park Thursday 6 October 2016
26 [Thu. 6 Apr. 2017] Prof. Rong-Jie Chein/Institute of Chemistry, Academia Sinica, Nankang, Taipei, Taiwan Prof. Rong-Jie Chein Thu. 6 Apr. 2017
25 [Thu. 30 Mar. 2017] Prof. Jeong Ho Cho/SKKU Advanced Institute of Nanotechnology (SAINT), School of Chemical Engineering, Sungkyunkwan University, Suwon, Korea Prof. Jeong Ho Cho Thu. 30 Mar. 2017
24 [Thu. 3 Nov. 2016] Prof. Min-Sik Kim/Mass spectrometry and its applications to Biological Discovery Prof. Min-Sik Kim Thursday 3 November 2016
23 [Thu. 29 Sep. 2016] Prof. Tae-Young Yoon/Observation of Single Membrane Proteins under Mechanical Tension Prof. Tae-Young Yoon Thursday 29 September 2016
22 [Thu. 27 Apr. 2017] Seminar was canceled! - -
21 [Thu. 26 Jun. 2016] Prof. Sung June Cho/Structural Elucidation of Novel Zeolite by Dual Space Approaches Using X-ray Powder Diffraction Prof. Sung June Cho Thursday 26 May 2016
20 [Thu. 25 May. 2017] Prof. Wonsuk Kim/Department of Chemistry and Nano Science, Ewha Womans University, Seoul Prof. Wonsuk Kim Thu. 25 May. 2017
19 [Thu. 23 Mar. 2017] Prof. Sangsu Bae/Department of Chemistry, Hanyang University, Seoul, South Korea Prof. Sangsu Bae Thu. 23 Mar. 2017
» [Thu. 22 Sep. 2016] Prof. Anna Lee/Organocatalyzed Asymmetric Reactions Prof. Anna Lee Thursday 22 September 2016
17 [Thu. 20 Oct. 2016] Prof. Chan Hyuk Kim/Novel Small Molecule-based Approaches for Cancer Immunotherapy Prof. Chan Hyuk Kim Thursday 20 October 2016
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15 [Thu. 19 May. 2016] Prof. Zhuang Liu/Nanotechnology for enhanced cancer radiation therapy and immunotherapy Prof. Zhuang Liu Thursday 19 May 2016
14 [Thu. 18 May. 2017] Student Host Colloquium : 1,1-Bisborylalkane: New Class of Organoboron Compound for the Chemo, Regio and Stereoselective Organic Transformations Prof. Seung Hwan Cho Thu. 18 May. 2017
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