New Chemistry of Ru-Alkylidenes from Metathesis to Arynes
Lee Daesung
Professor Daesung Lee (University of Illinois, Chicago, Department of Chemistry)
Host: Professor Jiyong Hong
Tuesday, January 15, 2019 - 11:40am to 1:10pm
Location: French Family Science Center 2237
Rosenthal, Janet

Link for Professor Lee

Abstract:  The main utility of Grubbs-type Ru-alkylidenes deals with metathesis chemistry. These Ru-complexes, however, have proven their potential as a precatalyst for many non-metathesis processes such as hydrogenation, dihydroxylation, cyclopropanation, and hydrovinylation. In light of expanding the scope of enyne metathesis, we have streamlined enyne metathesis and metallotropic [1,3]-shift such that various enyne-based functional groups could be constructed. Also, it was demonstrated that by the tandem catalytic sequence of Ru-alkylidenes, various Ru-chelated complexes could be trapped and isolated.  While exploring the tandem reactions of bis-1,3-diyne substrates, an unprecedented hydrovinylation reaction was discovered when ethylene was employed as an alkene counterpart. Furthermore, these bis-1,3-diynes can undergo hexadehydro Diels-Alder reaction to form aryne intermediates, which are hydrohalogenated by halohydrocarbons activated by Ru-alkylidene. In this presentation, the discovery of new reactions based on Ru-alkylidenes and the development of a variety of novel transformations involving aryne intermediate will be discussed.