|Speaker||Prof. Sung-Gon Kim|
|Date||Thu. 23 Nov. 2017|
|Venue||#331, Asan Hall, College of Science|
“Organocatalytic Cascade Reactions for the Asymmetric Synthesis
of Fused-ring Compounds”
Fused-ring structural units including chroman, indoline, pyrrolidine and hydroqunoline are widely distributed in nature and many biologically active compounds. Molecules containing these structural units exhibit a broad range of bioactivities such as anticancer, antiviral, antitumar, antimicrobial, sex pheromone, and central nervous system activity. Owing to the importance of these class of compounds, the stereoselective synthesis of fused-ring compounds is a noteworthy synthetic goal. In this presentation, we demonstrate the asymmetric synthesis of hydroquinoline, hydroquinazoline, and indolines via catalytic cascade reaction.
First, A synthetic method for the construction of fully substituted enantioenriched 1,4-dihydroquinolines using an organocatalytic aza-Michael/Michael cascade reaction has been developed (Sheme 1). 1 The asymmetric reaction of 2-(tosylamino)phenyl α,β-unsaturated ketones with alkynyl aldehydes, promoted by diphenylprolinol O-TMS ether as an organocatalyst, generated chiral 1,4-dihydroquinolines in good to high yields with excellent enantioselectivities (up to 97% ee)
We have also found a concise synthetic route to valuable highly functionalized benzosulfamidate-fused tetrahydroquinazoline (Scheme 2).2 The [4+2] cycloaddition of o-N-Cbz-amino-b-nitrostyrene with benzoxathiazine 2,2-dioxide using an imidazole as the catalyst afforded tetrahydroquinazolines with high diastereoselectivities.
In addition, we have established the synthesis of chiral benzosulfamidate-fused pyrrolidines through an Mannich/aza-Michael cascade reaction of δ-formyl-a,b-unsaturated ketones with cyclic N-sulfimines (Scheme 3).3 This simple domino process afforded diverse highly functionalized pyrrolidines in good yields with high diastero- and enantioselectivities.
1. Lee, Y.; Heo, S.; Kim, S.-G. Adv. Synth. Catal. 2015, 357, 1545-1550.
2. Sim, J.-T.; Kim, H. Kim, S.-G. Tetrahedron Lett. 2016, 57, 5907-5910.
3. Kim, H.; Kim, Y.; Kim, S.-G. J. Org. Chem. 2017, 82, 8179-8185.
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|Notice||Spring semester 2019 Seminar Schedule||-||-|
|58||[April 4. 2019] Rational Design of Solid-State Materials with Asymmetric Coordination Environment||Prof. Kang Min Ok (Sogang University)||Thu. 4 Apr. 2019|
|57||[March 28. 2019] NMR Structural Studies of engineered novel antimicrobial peptides||Prof. Yongae Kim (Hankuk University of Foreign Studies)||Thu. 28 Mar. 2019|
|56||[March 21, 2019] Nanomaterials Design for Energy Conversion and Storage||Prof. Jong-Hyuk Park (Yonsei University)||Thu. 21 Mar. 2019|
|55||[March 27, 2019] Hyperpolarization Researches with NV center, 129Xe and Parahydrogen||Prof. Keunhong Jeong||March 27, 2019|
|54||[March 20, 2019] Challenges in molecular dynamics simulations of unfolded proteins and protein-DNA complexes||Dr. Jejoong Yoo||March 20, 2019|
|53||[March 5. 2019] Innovation@Agilent||Dr. Darlene Solomon (Agilent Technologies Inc.)||Tuesday. 5 March. 2019|
|52||[March 5. 2019] Prof. Michael J. Sailor/Treatment of S. aureus Bacterial Infections with Porous Silicon Nanoparticles||Prof. Michael J. Sailor (UC San Diego)||Tuesday. 5 March. 2019|
|51||[Thu. 6 Dec. 2018] Prof. Dong-Ho Kim/Department of Chemistry, Yonsei University, Seoul, Korea||Prof. Dong-Ho Kim (Yonsei University)||Thu. 6 Dec. 2018|
|50||Fall semester 2018 Seminar Schedule||-||-|
|49||[January 24, 2018] Electro-Optic Organic THz Wave Sources||Prof. O-Pil Kwon(Ajou University)||January 24, 2018 (Wednesday)|
|48||[Thu. 30 Nov. 2017] Prof. Sunmin Ryu/Department of Chemistry, POSTECH, Pohang, South Korea||Prof. Sunmin Ryu||Thu. 30 Nov. 2017|
|»||[Thu. 23 Nov. 2017] Prof. Sung-Gon Kim/Department of Chemistry, Kyonggi University, Suwon, Korea||Prof. Sung-Gon Kim||Thu. 23 Nov. 2017|
|46||[November 14, 2017] Zero-Point Energy, Fluctuations, and Dissipation : A (Mostly) Quantum-Optical Perspective||Prof. Milonni, Peter||November 14, 2017|
|45||[Thu. 16 Nov. 2017] Prof. Hyungjun Kim/Department of Chemistry, and Graduate school of Energy, Environment, Water, and Sustainability (EEWS), KAIST, Daejeon, Korea||Prof. Hyungjun Kim||Thu. 16 Nov. 2017|
|44||[Fri. 30 Oct. 2017] Prof. Igor Rodin/Department of Chemistry, Moscow State University, Moscow, Russia||Prof. Igor Rodin||Fri. 30 Oct. 201|
|43||[October 31, 2017] New ways of vision: Protein structures in translational medicine and business development, my experience||Prof. Robert Huber(1988 Nobel Prize in Chemistry)||October 31, 2017|
|42||[Thu. 26 Oct. 2017] Dr. Jung-Nyoung Heo/Center for Medicinal Chemistry Research, Korea Research Institute of Chemical Technology, Daejeon, Korea||Dr. Jung-Nyoung Heo||Thu. 26 Oct. 2017|
|41||[October 25, 2017] Ultrafast electron microscopy: applications in chemical and materials sciences||Dr. Byung-Kuk Yoo||October 25, 2017|
|40||[Mon. 16 Oct. 2017] Prof. Kirk S. Schanze/Department of Chemistry, University of Texas at San Antonio, Texas, USA||Prof. Kirk S. Schanze||Mon. 16 Oct. 2017|
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