6월8일(목) 대학원세미나 Prof. Won-jin Chung(Department of Chemistry, GIST, Gwangju, Republic of Korea)
|초청강사||Prof. Won-jin Chung|
|소속||Department of Chemistry, GIST, Gwangju, Republic of Korea|
|일시||2017년 6월 8일(목) 오후5시|
“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.
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