|Speaker||Prof. Won-jin Chung|
|Date||Thu. 8 Jun. 2017|
|Venue||#633, Asan Hall, College of Science|
“Part 1. A Catalytic Enantioselective Glycolate Aldol Reaction
via Lewis Base Activation of Lewis Acids”
Part 1. A general, efficient, Lewis-base catalyzed enantioselective addition of glycolate-derived silyl ketene acetals to a wide range of aldehydes will be presented. Both syn- and anti-diastereomers are accessible without changing the catalyst or controlling the geometry of the silyl ketene acetal. Simple modification of the size of alkyl groups on the silyl ketene acetal is sufficient to reverse the stereochemical course of the addition. The observed diastereoselectivity and reactivity could be rationalized by the analysis of six open transition state structures with the aid of computational analysis.
“Part 2. A General Enantioselective Approach to
the Chemical Synthesis of the Chlorosulfolipids”
Part 2. A concise and general approach has been developed for the enantioselective synthesis of three structurally related chlorosulfolipids. Key advances include highly stereocontrolled additions to a,b-dichloroaldehydes, kinetic resolution of complex chlorinated vinyl epoxide intermediates, and Z-selective alkene cross metathesis of cis-vinyl epoxides. This strategy facilitated the synthesis of enantioenriched danicalipin A, mytilipin A, and malhamensilipin A in nine, eight, and eleven steps, respectively.
1. Chung, W.-j.; Carlson, J. S.; Vanderwal, C. D. J. Org. Chem. 2014, 79, 2226–2241.
2. Chung, W.-j.; Vanderwal, C. D. Acc. Chem. Res. 2014, 47, 718–728.
3. Chung, W.-j.; Carlson, J. S.; Bedke, D. K.; Vanderwal, C. D. Angew. Chem. Int. Ed. 2013, 52, 10052–10055.
4. Denmark, S. E.; Chung, W.-j. J. Org. Chem. 2008, 73, 4582–4595.
5. Denmark, S. E.; Chung, W.-j. Angew. Chem. Int. Ed. 2008, 47, 1890–1892.
Prof. Won-jin Chung
Department of Chemistry, GIST, Gwangju, Republic of Korea
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|Notice||Spring semester 2017 Seminar Schedule||-||-|
|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||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|
|»||[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|
|18||[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|
|16||[Thu. 2 Jun. 2016] Prof. Sunkyu Han/Total Syntheses of Complex Alkaloids Inspired by Biosynthetic Hypotheses||Prof. Sunkyu Han||Thursday 2 June 2016|
|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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