【28th.June】Chiral Cationic Ion-Pairing Catalysts
日期：2019-06-28
阅读：634
TOPIC：Chiral Cationic Ion-Pairing Catalysts
SPEAKER：Prof. Choon Hong Tan, Nanyang Technological University
TIME：2019年6月28日（周五）上午9:30
LOCATION：材料A楼500会议室
INVITER：涂永强院士 周永丰教授 张书宇特别研究员
Biography：
Prof. Tan received his BSc (Hons), First Class from the National University of Singapore in 1995 and completed his PhD from the University of Cambridge in 1999. Following that, he carried out two years postdoctoral training at the Department of Chemistry and Chemical Biology, Harvard University. Subsequently, he worked as a Research Associate at Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School for another year before joined the Department of Chemistry, National University of Singapore as Assistant Professor in 2003. He was then promoted to Associate Professor in 2010. He joined Nanyang Technological University in 2012 as an Associate Professor and was promoted to Full Professor in 2016.
Professor Tan’s research interest is in the field of Synthetic Organic Chemistry and Catalysis. He also conducts research in the field of catalysis, in particular the development of new catalysts towards practical asymmetric synthesis. Over the years, Professor Tan had published many top quality journal papers and has more than 127 journal papers with current citation count of more than 6800. His H-Index is 47.
Abstract：
Phase transfer reactions using chiral cations and inorganic basic salts such as hydroxides and carbonates are but a sub-set of a larger group of reactions known as chiral cation ion-pairing catalysis. Herein, we report three reactions using chiral dicationic bisguanidinium ion pairs as catalysis; they are are each paired with three different organometallic anions – permanganate, tungstate and molybdate. The ion pairs-catalyzed asymmetric oxidation of alkenes and sulfoxidation respectively. In this new mode of catalysis, evidence suggests that rate acceleration is mainly attributed to transition state stabilization through attractive cation-anion interaction rather than enhancing solubility in organic solvents.
