1. Department of Chemistry Seminar Announcement Date/Time/VenueTitle/Speaker 25 Jan (Tue) 11am – 12nn @ S8 Level 3 Executive Classroom Rh-Catalyzed [(5+2)+1], [7+1], [3+2], and [(3+2)+1] Cycloadditions Professor Yu Zhixiang Peking University, China Host : Asst Prof Wang Jian About the Speaker All are Welcome Prof. Zhi-Xiang Yu (1991, B.S., Wuhan University; 1997, M.S., Peking University; 2001, Ph. D., Hong Kong University of Science & Technology; 2001-2004, Postdoctoral associate, University of California, Los Angeles) started his independent career as an associate professor at Peking University in 2004 and was promoted to a full professor in 2008. He and his group are applying both computational and synthetic organic chemistry to study reaction mechanisms, to discover, design and develop new reactions, and to synthesize natural products. Prof. Yu is one of the National Science Fund for Distinguished Young Scholars of China in 2008 and won the Young Chemist Award, the Chinese Chemical Society & the Royal Society of Chemistry in 2008. Abstract Discovering and developing transition metal catalyzed [m+n], [m+n+o], [m+n+o+x] cycloadditions to reach various cyclic compounds are important for the “ideal synthesis” of functional molecules, which usually have various-sized ring skeletons that are not easy or difficult to be accessed by the traditional organic reactions. Recently we developed several rhodium catalyzed cycloaddition reactions of vinylcyclopropanes with alkynes, alkenes, allenes, and CO to construct five-, six-, and eight-membered carbocycles with the aid of calculations (see these [(5+2)+1], [7+1], [3+2], and [(3+2)+1] cycloadditions in the scheme below). Some of these reactions have been applied to the synthesis of natural products to demonstrate the impacts of these cycloaddition reactions on synthesis.

2. Department of Chemistry Seminar Announcement Date/Time/VenueTitle/Speaker 27 Jan (Thu) 3pm – 4pm @ S8 Level 3 Executive Classroom Water Catalysis in [1,n]-Hydrogen Shifts Professor Yu Zhixiang Peking University, China Host : Assoc Prof Lu Yixin About the Speaker All are Welcome Prof. Zhi-Xiang Yu (1991, B.S., Wuhan University; 1997, M.S., Peking University; 2001, Ph. D., Hong Kong University of Science & Technology; 2001-2004, Postdoctoral associate, University of California, Los Angeles) started his independent career as an associate professor at Peking University in 2004 and was promoted to a full professor in 2008. He and his group are applying both computational and synthetic organic chemistry to study reaction mechanisms, to discover, design and develop new reactions, and to synthesize natural products. Prof. Yu is one of the National Science Fund for Distinguished Young Scholars of China in 2008 and won the Young Chemist Award, the Chinese Chemical Society & the Royal Society of Chemistry in 2008. Abstract [1,n]-hydrogen shifts are widely found in organic and enzymatic reactions. However, details of their reaction mechanisms are usually not available. Some [1,n]-hydrogen shifts are difficult to occur, as judged from the orbital interaction and symmetry considerations. In these cases, some “mysterious” catalysts must play roles to catalyze these [1,n]-hydrogen shifts. In this talk, through several examples, 1-5 we want to show that the inadvertent water in the organic reaction systems, or the water solvent itself in aqueous reaction systems, can act as the “mysterious” catalyst to facilitate the otherwise difficult [1,n]-hydrogen shifts. References: 1.Xia, Y., Liang, Y., Chen, Y., Wang, M., Jiao, L., Huang, F., Li, S., Li, Y., and Yu, Z.-X., J. Am. Chem. Soc. 2007, 129, 3470. 2.Liang, Y., Liu, S., Xia, Y., Li Y., Yu, Z.-X. Chem. Eur. J. 2008, 14, 4361. 3.Shi, F., Li, X., Xia, Y., Zhang, L., Yu, Z.-X., J. Am. Chem. Soc. 2007, 129, 15503. 4.Liang Y.; Liu S., Yu, Z.-X. Synlett, 2009, 905. 5.Liang Y., Zhou, H. Yu, Z.-X. J. Am. Chem. Soc. 2009, 131, 17783.