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다음주 월요일(10월 13일)에 세미나가 개최됩니다.이번 세미나는 1층 330126호에서 진행됩니다.
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제 목 : Three-Membered Rings and Triple Bonds as Ideal Starting Materials for Domino Cascades
연 사 : Prof. Daniel B. Werz (Institute of Organic Chemistry, Department of Life Sciences, Technische Universität Braunschweig)
일 시 : 2014년 10월 13일 (월) 오후 4시 30분
장 소 : 화학관 1층 첨단강의실 (330126호실)
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Three-Membered Rings and Triple Bonds as Ideal Starting Materials for Domino Cascades
Cyclopropanes as well as carbon-carbon triple bonds are systems being high in energy. Therefore, both moieties are ideally suited for a cascade of consecutive reactions (domino reactions).
In a first part, domino reactions based on ring-enlargement reactions of donor-acceptor-substituted cyclopropanes[1] are discussed. Aldehyde, ketimines and thioketones are utilized as acceptors whereas ether moieties serve as donor.[2]A rearrangement leads to the respective five-membered rings which tend to eliminate water. As a result, aromatic systems are formed.[2]Depending on the substrate domino cascades are initiated which are able to transform the biscyclopropane derivative 1 in one step into the corresponding quaterpyrrol 2. In a second part, Pd-catalyzed domino reactions starting with triple bonds attached to carbohydrate derivatives 4 are reported to construct a variety of chroman- and isochroman-type structures such as 5.[3] Such domino sequences are also employed to a variety of other processes leading to complex scaffolds in a facile and efficient fashion.
References
[1] H.-U. Reißig, R. Zimmer, Chem. Rev. 2003, 103, 1151-1196.
[2] a) T. F. Schneider, J. Kaschel, B. Dittrich, D. B. Werz, Org. Lett. 2009, 11, 2317-2320; b) T. F. Schneider, J. Kaschel, S. I. Awan, B. Dittrich, D. B. Werz, Chem. Eur. J. 2010, 16, 11276-11288; c) J. Kaschel, T. F. Schneider, D. Kratzert, D. Stalke, D. B. Werz, Angew. Chem. Int. Ed. 2012, 51, 11153-11156. d) J. Kaschel, C. D. Schmidt, M. Mumby, D. Kratzert, D. Stalke, D. B. Werz, Chem. Commun. 2013, 49, 4403-4405.
[3] a) M. Leibeling, D. C. Koester, M. Pawliczek, S. C. Schild, D. B. Werz, Nature Chem. Biol. 2010,6, 199-201; b) M. Leibeling, B. Milde, D. Kratzert, D. Stalke, D. B. Werz, Chem. Eur. J. 2011, 17, 9888-9892; c) M. Leibeling, D. B. Werz, Chem. Eur. J. 2012, 18, 6138-6141; d) M. Leibeling, M. Pawliczek, D. Kratzert, D. Stalke, D. B. Werz, Org. Lett. 2012, 14, 346-349.